专辑：MySQL教程_MySQL的一些基础知识-Java充电社【公众号：Java充电社】

这是mysql系列第1篇。

## 本文主要内容

1. 背景介绍
2. 数据库基础知识介绍
3. mysql的安装
4. mysql常用的一些命令介绍
5. SQL分类

## 背景介绍

我们每天都在访问各种网站、APP，如微信、QQ、抖音、今日头条、腾讯新闻等，这些东西上面都存在大量的信息，这些信息都需要有地方存储，存储在哪呢？数据库。

所以如果我们需要开发一个网站、app，数据库我们必须掌握的技术，常用的数据库有mysql、oracle、sqlserver、db2等。

上面介绍的几个数据库，oracle性能排名第一，服务也是相当到位的，但是收费也是非常高的，金融公司对数据库稳定性要求比较高，一般会选择oracle。

mysql是免费的，其他几个目前暂时收费的，mysql在互联网公司使用率也是排名第一，资料也非常完善，社区也非常活跃，所以我们主要学习mysql。

## mysql系列我们主要介绍

1. mysql的基本使用
2. mysql性能优化
3. 开发过程中mysql一些优秀的案例介绍

## 数据库常见的概念

**DB**：数据库，存储数据的容器。

**DBMS**：数据库管理系统，又称为数据库软件或数据库产品，用于创建或管理DB。

**SQL**：结构化查询语言，用于和数据库通信的语言，不是某个数据库软件持有的，而是几乎所有的主流数据库软件通用的语言。中国人之间交流需要说汉语，和美国人之间交流需要说英语，和数据库沟通需要说SQL语言。

## 数据库存储数据的一些特点

- 数据存放在表中，然后表存放在数据库中

- 一个库中可以有多张表，每张表具有唯一的名称（表名）来标识自己

- 表中有一个或多个列，列又称为“字段”，相当于java中的“属性”

- 表中每一行数据，相当于java中的“对象”

## window中安装mysql

官网下载mysql5.7.25：`https://dev.mysql.com/downloads/mysql/5.7.html#downloads`

**win10安装mysql5.7详细步骤可以看：`http://itsoku.com/course/3/211`**

## mysql常用的一些命令

### mysql启动2种方式

**方式1：**

cmd中运行`services.msc`

![](https://itsoku.oss-cn-hangzhou.aliyuncs.com/itsoku/blog/article/35/d2024d07-736b-40f7-af86-3657c6640e5b.png)

会打开服务窗口，在服务窗口中找到mysql服务，点击右键可以启动或者停止

![](https://itsoku.oss-cn-hangzhou.aliyuncs.com/itsoku/blog/article/35/6fc27a24-2994-4d6a-989f-30087c683d9e.png)

![](https://itsoku.oss-cn-hangzhou.aliyuncs.com/itsoku/blog/article/35/08d69c93-abb7-4ad5-b3e4-d199603254e4.png)

**方式2**

以管理员身份运行cmd命令

![](https://itsoku.oss-cn-hangzhou.aliyuncs.com/itsoku/blog/article/35/84a01ee3-5d8d-4ff0-9a8d-704d7d7eb461.png)

**停止命令：net stop mysql**

**启动命令：net start mysql**

```java
C:\Windows\system32>net stop mysql
mysql 服务正在停止.
mysql 服务已成功停止。

C:\Windows\system32>net start mysql
mysql 服务正在启动 .
mysql 服务已经启动成功。
```

**注意：命令后面没有结束符号**

### mysql登录命令

> mysql -h ip -P 端口 -u 用户名 -p

```shell
C:\Windows\system32>mysql -h localhost -P 3306 -u root -p
Enter password: *******
Welcome to the MySQL monitor.  Commands end with ; or \g.
Your MySQL connection id is 10
Server version: 5.7.25-log MySQL Community Server (GPL)

Oracle is a registered trademark of Oracle Corporation and/or its
affiliates. Other names may be trademarks of their respective
owners.

Type 'help;' or '\h' for help. Type '\c' to clear the current input statement.
```

**说明：**

- -P 大写的P后面跟上端口

- 如果是登录本金ip和端口可以省略，如：

```java
  mysql -u 用户名 -p
  ```

- 可以通过上面的命令连接原创机器的mysql

### 查看数据库版本

> `mysql --version 或者mysql -V`用于在未登录情况下，查看本机mysql版本：

```shell
C:\Windows\system32>mysql -V
mysql  Ver 14.14 Distrib 5.7.25, for Win64 (x86_64)

C:\Windows\system32>mysql --version
mysql  Ver 14.14 Distrib 5.7.25, for Win64 (x86_64)
```

> `select version();`：登录情况下，查看链接的库版本：

```shell
mysql> select version();
+------------+
| version()  |
+------------+
| 5.7.25-log |
+------------+
1 row in set (0.00 sec)
```

### 显示所有数据库：**show databases;**

### 进入指定的库：**use 库名;**

```shell
mysql> use seata;
Database changed
```

### 显示当前库中所有的表：**show tables;**

### 查看其他库中所有的表：**show tables from 库名;**

### 查看表的创建语句：**show create table 表名;**

```shell
mysql> show create table biz_tags;
+----------+---------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------+
| Table    | Create Table                                                                                                                                                                                                                                                                                                                                                                                                                                                  |
+----------+---------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------+
| biz_tags | CREATE TABLE `biz_tags` (
  `id` bigint(20) unsigned NOT NULL AUTO_INCREMENT,
  `name` varchar(50) NOT NULL COMMENT '书签名',
  `description` varchar(100) DEFAULT NULL COMMENT '描述',
  `create_time` datetime DEFAULT CURRENT_TIMESTAMP COMMENT '添加时间',
  `update_time` datetime DEFAULT CURRENT_TIMESTAMP COMMENT '更新时间',
  PRIMARY KEY (`id`) USING BTREE
) ENGINE=InnoDB AUTO_INCREMENT=21 DEFAULT CHARSET=utf8 ROW_FORMAT=COMPACT              |
+----------+---------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------+
1 row in set (0.00 sec)
```

### 查看表结构：**desc 表名;**

### 查看当前所在库：**select database();**

```shell
C:\Windows\system32>mysql -h localhost -P 3306 -u root -p
Enter password: *******
Welcome to the MySQL monitor.  Commands end with ; or \g.
Your MySQL connection id is 7
Server version: 5.7.25-log MySQL Community Server (GPL)

Oracle is a registered trademark of Oracle Corporation and/or its
affiliates. Other names may be trademarks of their respective
owners.

Type 'help;' or '\h' for help. Type '\c' to clear the current input statement.

mysql> select database();
+------------+
| database() |
+------------+
| NULL       |
+------------+
1 row in set (0.00 sec)

mysql> use dblog;
Database changed
mysql> select database();
+------------+
| database() |
+------------+
| dblog      |
+------------+
1 row in set (0.00 sec)
```

### 查看当前mysql支持的存储引擎：SHOW ENGINES;

```shell
mysql> SHOW ENGINES;
+--------------------+---------+----------------------------------------------------------------+--------------+------+------------+
| Engine             | Support | Comment                                                        | Transactions | XA   | Savepoints |
+--------------------+---------+----------------------------------------------------------------+--------------+------+------------+
| InnoDB             | DEFAULT | Supports transactions, row-level locking, and foreign keys     | YES          | YES  | YES        |
| MRG_MYISAM         | YES     | Collection of identical MyISAM tables                          | NO           | NO   | NO         |
| MEMORY             | YES     | Hash based, stored in memory, useful for temporary tables      | NO           | NO   | NO         |
| BLACKHOLE          | YES     | /dev/null storage engine (anything you write to it disappears) | NO           | NO   | NO         |
| MyISAM             | YES     | MyISAM storage engine                                          | NO           | NO   | NO         |
| CSV                | YES     | CSV storage engine                                             | NO           | NO   | NO         |
| ARCHIVE            | YES     | Archive storage engine                                         | NO           | NO   | NO         |
| PERFORMANCE_SCHEMA | YES     | Performance Schema                                             | NO           | NO   | NO         |
| FEDERATED          | NO      | Federated MySQL storage engine                                 | NULL         | NULL | NULL       |
+--------------------+---------+----------------------------------------------------------------+--------------+------+------------+
9 rows in set (0.00 sec)
```

### 查看系统变量及其值：SHOW VARIABLES;

```shell
mysql> SHOW VARIABLES;
+----------------------------------------------------------+------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------+
| Variable_name                                            | Value                                                                                                                                                                                                                                                                                                                                                                                                            |
+----------------------------------------------------------+------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------+
| auto_increment_increment                                 | 1                                                                                                                                                                                                                                                                                                                                                                                                                |
| auto_increment_offset                                    | 1                                                                                                                                                                                                                                                                                                                                                                                                                |
| autocommit                                               | ON                                                                                                                                                                                                                                                                                                                                                                                                               |
| automatic_sp_privileges                                  | ON                                                                                                                                                                                                                                                                                                                                                                                                               |
| avoid_temporal_upgrade                                   | OFF                                                                                                                                                                                                                                                                                                                                                                                                              |
| back_log                                                 | 90                                                                                                                                                                                                                                                                                                                                                                                                               |
| basedir                                                  | D:\installsoft\MySQL\mysql-5.7.25-winx64\                                                                                                                                                                                                                                                                                                                                                                        |
| big_tables                                               | OFF                                                                                                                                                                                                                                                                                                                                                                                                              |
| bind_address                                             | *                                                                                                                                                                                                                                                                                                                                                                                                                |
| binlog_cache_size                                        | 32768                                                                                                                                                                                                                                                                                                                                                                                                            |
| binlog_checksum                                          | CRC32                                                                                                                                                                                                                                                                                                                                                                                                            |
| binlog_direct_non_transactional_updates                  | OFF                                                                                                                                                                                                                                                                                                                                                                                                              |
| binlog_error_action                                      | ABORT_SERVER                                                                                                                                                                                                                                                                                                                                                                                                     |
| binlog_format                                            | ROW                                                                                                                                                                                                                                                                                                                                                                                                              |
| binlog_group_commit_sync_delay                           | 0                                                                                                                                                                                                                                                                                                                                                                                                                |
| binlog_group_commit_sync_no_delay_count                  | 0                                                                                                                                                                                                                                                                                                                                                                                                                |
| binlog_gtid_simple_recovery                              | ON                                                                                                                                                                                                                                                                                                                                                                                                               |
| binlog_max_flush_queue_time                              | 0                                                                                                                                                                                                                                                                                                                                                                                                                |
| binlog_order_commits                                     | ON                                                                                                                                                                                                                                                                                                                                                                                                               |
| binlog_row_image                                         | FULL                                                                                                                                                                                                                                                                                                                                                                                                             |
| binlog_rows_query_log_events                             | OFF                                                                                                                                                                                                                                                                                                                                                                                                              |
| binlog_stmt_cache_size                                   | 32768                                                                                                                                                                                                                                                                                                                                                                                                            |
| binlog_transaction_dependency_history_size               | 25000                                                                                                                                                                                                                                                                                                                                                                                                            |
| binlog_transaction_dependency_tracking                   | COMMIT_ORDER                                                                                                                                                                                                                                                                                                                                                                                                     |
| block_encryption_mode                                    | aes-128-ecb                                                                                                                                                                                                                                                                                                                                                                                                      |
| bulk_insert_buffer_size                                  | 8388608                                                                                                                                                                                                                                                                                                                                                                                                          |
| character_set_client                                     | utf8                                                                                                                                                                                                                                                                                                                                                                                                             |
| character_set_connection                                 | utf8                                                                                                                                                                                                                                                                                                                                                                                                             |
| character_set_database                                   | utf8mb4                                                                                                                                                                                                                                                                                                                                                                                                          |
| character_set_filesystem                                 | binary                                                                                                                                                                                                                                                                                                                                                                                                           |
| character_set_results                                    | utf8                                                                                                                                                                                                                                                                                                                                                                                                             |
| character_set_server                                     | utf8                                                                                                                                                                                                                                                                                                                                                                                                             |
| character_set_system                                     | utf8                                                                                                                                                                                                                                                                                                                                                                                                             |
| character_sets_dir                                       | D:\installsoft\MySQL\mysql-5.7.25-winx64\share\charsets\                                                                                                                                                                                                                                                                                                                                                         |
| check_proxy_users                                        | OFF                                                                                                                                                                                                                                                                                                                                                                                                              |
| collation_connection                                     | utf8_general_ci                                                                                                                                                                                                                                                                                                                                                                                                  |
| collation_database                                       | utf8mb4_bin                                                                                                                                                                                                                                                                                                                                                                                                      |
| collation_server                                         | utf8_general_ci                                                                                                                                                                                                                                                                                                                                                                                                  |
| completion_type                                          | NO_CHAIN                                                                                                                                                                                                                                                                                                                                                                                                         |
| concurrent_insert                                        | AUTO                                                                                                                                                                                                                                                                                                                                                                                                             |
| connect_timeout                                          | 10                                                                                                                                                                                                                                                                                                                                                                                                               |
| core_file                                                | OFF                                                                                                                                                                                                                                                                                                                                                                                                              |
| datadir                                                  | D:\installsoft\MySQL\mysql-5.7.25-winx64\data\                                                                                                                                                                                                                                                                                                                                                                   |
| date_format                                              | %Y-%m-%d                                                                                                                                                                                                                                                                                                                                                                                                         |
| datetime_format                                          | %Y-%m-%d %H:%i:%s                                                                                                                                                                                                                                                                                                                                                                                                |
| default_authentication_plugin                            | mysql_native_password                                                                                                                                                                                                                                                                                                                                                                                            |
| default_password_lifetime                                | 0                                                                                                                                                                                                                                                                                                                                                                                                                |
| default_storage_engine                                   | InnoDB                                                                                                                                                                                                                                                                                                                                                                                                           |
| default_tmp_storage_engine                               | InnoDB                                                                                                                                                                                                                                                                                                                                                                                                           |
| default_week_format                                      | 0                                                                                                                                                                                                                                                                                                                                                                                                                |
| delay_key_write                                          | ON                                                                                                                                                                                                                                                                                                                                                                                                               |
| delayed_insert_limit                                     | 100                                                                                                                                                                                                                                                                                                                                                                                                              |
| delayed_insert_timeout                                   | 300                                                                                                                                                                                                                                                                                                                                                                                                              |
| delayed_queue_size                                       | 1000                                                                                                                                                                                                                                                                                                                                                                                                             |
| disabled_storage_engines                                 |                                                                                                                                                                                                                                                                                                                                                                                                                  |
| disconnect_on_expired_password                           | ON                                                                                                                                                                                                                                                                                                                                                                                                               |
| div_precision_increment                                  | 4                                                                                                                                                                                                                                                                                                                                                                                                                |
| end_markers_in_json                                      | OFF                                                                                                                                                                                                                                                                                                                                                                                                              |
| enforce_gtid_consistency                                 | OFF                                                                                                                                                                                                                                                                                                                                                                                                              |
| eq_range_index_dive_limit                                | 200                                                                                                                                                                                                                                                                                                                                                                                                              |
| error_count                                              | 0                                                                                                                                                                                                                                                                                                                                                                                                                |
| event_scheduler                                          | OFF                                                                                                                                                                                                                                                                                                                                                                                                              |
| expire_logs_days                                         | 0                                                                                                                                                                                                                                                                                                                                                                                                                |
| explicit_defaults_for_timestamp                          | OFF                                                                                                                                                                                                                                                                                                                                                                                                              |
| external_user                                            |                                                                                                                                                                                                                                                                                                                                                                                                                  |
| flush                                                    | OFF                                                                                                                                                                                                                                                                                                                                                                                                              |
| flush_time                                               | 0                                                                                                                                                                                                                                                                                                                                                                                                                |
| foreign_key_checks                                       | ON                                                                                                                                                                                                                                                                                                                                                                                                               |
| ft_boolean_syntax                                        | + -><()~*:""&|                                                                                                                                                                                                                                                                                                                                                                                                   |
| ft_max_word_len                                          | 84                                                                                                                                                                                                                                                                                                                                                                                                               |
| ft_min_word_len                                          | 4                                                                                                                                                                                                                                                                                                                                                                                                                |
| ft_query_expansion_limit                                 | 20                                                                                                                                                                                                                                                                                                                                                                                                               |
| ft_stopword_file                                         | (built-in)                                                                                                                                                                                                                                                                                                                                                                                                       |
| general_log                                              | OFF                                                                                                                                                                                                                                                                                                                                                                                                              |
| general_log_file                                         | D:\installsoft\MySQL\mysql-5.7.25-winx64\data\DESKTOP-3OB6NA3.log                                                                                                                                                                                                                                                                                                                                                |
| group_concat_max_len                                     | 1024                                                                                                                                                                                                                                                                                                                                                                                                             |
| gtid_executed_compression_period                         | 1000                                                                                                                                                                                                                                                                                                                                                                                                             |
| gtid_mode                                                | OFF                                                                                                                                                                                                                                                                                                                                                                                                              |
| gtid_next                                                | AUTOMATIC                                                                                                                                                                                                                                                                                                                                                                                                        |
| gtid_owned                                               |                                                                                                                                                                                                                                                                                                                                                                                                                  |
| gtid_purged                                              |                                                                                                                                                                                                                                                                                                                                                                                                                  |
| have_compress                                            | YES                                                                                                                                                                                                                                                                                                                                                                                                              |
| have_crypt                                               | NO                                                                                                                                                                                                                                                                                                                                                                                                               |
| have_dynamic_loading                                     | YES                                                                                                                                                                                                                                                                                                                                                                                                              |
| have_geometry                                            | YES                                                                                                                                                                                                                                                                                                                                                                                                              |
| have_openssl                                             | DISABLED                                                                                                                                                                                                                                                                                                                                                                                                         |
| have_profiling                                           | YES                                                                                                                                                                                                                                                                                                                                                                                                              |
| have_query_cache                                         | YES                                                                                                                                                                                                                                                                                                                                                                                                              |
| have_rtree_keys                                          | YES                                                                                                                                                                                                                                                                                                                                                                                                              |
| have_ssl                                                 | DISABLED                                                                                                                                                                                                                                                                                                                                                                                                         |
| have_statement_timeout                                   | YES                                                                                                                                                                                                                                                                                                                                                                                                              |
| have_symlink                                             | YES                                                                                                                                                                                                                                                                                                                                                                                                              |
| host_cache_size                                          | 328                                                                                                                                                                                                                                                                                                                                                                                                              |
| hostname                                                 | DESKTOP-3OB6NA3                                                                                                                                                                                                                                                                                                                                                                                                  |
| identity                                                 | 0                                                                                                                                                                                                                                                                                                                                                                                                                |
| ignore_builtin_innodb                                    | OFF                                                                                                                                                                                                                                                                                                                                                                                                              |
| ignore_db_dirs                                           |                                                                                                                                                                                                                                                                                                                                                                                                                  |
| init_connect                                             |                                                                                                                                                                                                                                                                                                                                                                                                                  |
| init_file                                                |                                                                                                                                                                                                                                                                                                                                                                                                                  |
| init_slave                                               |                                                                                                                                                                                                                                                                                                                                                                                                                  |
| innodb_adaptive_flushing                                 | ON                                                                                                                                                                                                                                                                                                                                                                                                               |
| innodb_adaptive_flushing_lwm                             | 10                                                                                                                                                                                                                                                                                                                                                                                                               |
| innodb_adaptive_hash_index                               | ON                                                                                                                                                                                                                                                                                                                                                                                                               |
| innodb_adaptive_hash_index_parts                         | 8                                                                                                                                                                                                                                                                                                                                                                                                                |
| innodb_adaptive_max_sleep_delay                          | 150000                                                                                                                                                                                                                                                                                                                                                                                                           |
| innodb_api_bk_commit_interval                            | 5                                                                                                                                                                                                                                                                                                                                                                                                                |
| innodb_api_disable_rowlock                               | OFF                                                                                                                                                                                                                                                                                                                                                                                                              |
| innodb_api_enable_binlog                                 | OFF                                                                                                                                                                                                                                                                                                                                                                                                              |
| innodb_api_enable_mdl                                    | OFF                                                                                                                                                                                                                                                                                                                                                                                                              |
| innodb_api_trx_level                                     | 0                                                                                                                                                                                                                                                                                                                                                                                                                |
| innodb_autoextend_increment                              | 64                                                                                                                                                                                                                                                                                                                                                                                                               |
| innodb_autoinc_lock_mode                                 | 1                                                                                                                                                                                                                                                                                                                                                                                                                |
| innodb_buffer_pool_chunk_size                            | 134217728                                                                                                                                                                                                                                                                                                                                                                                                        |
| innodb_buffer_pool_dump_at_shutdown                      | ON                                                                                                                                                                                                                                                                                                                                                                                                               |
| innodb_buffer_pool_dump_now                              | OFF                                                                                                                                                                                                                                                                                                                                                                                                              |
| innodb_buffer_pool_dump_pct                              | 25                                                                                                                                                                                                                                                                                                                                                                                                               |
| innodb_buffer_pool_filename                              | ib_buffer_pool                                                                                                                                                                                                                                                                                                                                                                                                   |
| innodb_buffer_pool_instances                             | 1                                                                                                                                                                                                                                                                                                                                                                                                                |
| innodb_buffer_pool_load_abort                            | OFF                                                                                                                                                                                                                                                                                                                                                                                                              |
| innodb_buffer_pool_load_at_startup                       | ON                                                                                                                                                                                                                                                                                                                                                                                                               |
| innodb_buffer_pool_load_now                              | OFF                                                                                                                                                                                                                                                                                                                                                                                                              |
| innodb_buffer_pool_size                                  | 134217728                                                                                                                                                                                                                                                                                                                                                                                                        |
| innodb_change_buffer_max_size                            | 25                                                                                                                                                                                                                                                                                                                                                                                                               |
| innodb_change_buffering                                  | all                                                                                                                                                                                                                                                                                                                                                                                                              |
| innodb_checksum_algorithm                                | crc32                                                                                                                                                                                                                                                                                                                                                                                                            |
| innodb_checksums                                         | ON                                                                                                                                                                                                                                                                                                                                                                                                               |
| innodb_cmp_per_index_enabled                             | OFF                                                                                                                                                                                                                                                                                                                                                                                                              |
| innodb_commit_concurrency                                | 0                                                                                                                                                                                                                                                                                                                                                                                                                |
| innodb_compression_failure_threshold_pct                 | 5                                                                                                                                                                                                                                                                                                                                                                                                                |
| innodb_compression_level                                 | 6                                                                                                                                                                                                                                                                                                                                                                                                                |
| innodb_compression_pad_pct_max                           | 50                                                                                                                                                                                                                                                                                                                                                                                                               |
| innodb_concurrency_tickets                               | 5000                                                                                                                                                                                                                                                                                                                                                                                                             |
| innodb_data_file_path                                    | ibdata1:12M:autoextend                                                                                                                                                                                                                                                                                                                                                                                           |
| innodb_data_home_dir                                     |                                                                                                                                                                                                                                                                                                                                                                                                                  |
| innodb_deadlock_detect                                   | ON                                                                                                                                                                                                                                                                                                                                                                                                               |
| innodb_default_row_format                                | dynamic                                                                                                                                                                                                                                                                                                                                                                                                          |
| innodb_disable_sort_file_cache                           | OFF                                                                                                                                                                                                                                                                                                                                                                                                              |
| innodb_doublewrite                                       | ON                                                                                                                                                                                                                                                                                                                                                                                                               |
| innodb_fast_shutdown                                     | 1                                                                                                                                                                                                                                                                                                                                                                                                                |
| innodb_file_format                                       | Barracuda                                                                                                                                                                                                                                                                                                                                                                                                        |
| innodb_file_format_check                                 | ON                                                                                                                                                                                                                                                                                                                                                                                                               |
| innodb_file_format_max                                   | Barracuda                                                                                                                                                                                                                                                                                                                                                                                                        |
| innodb_file_per_table                                    | ON                                                                                                                                                                                                                                                                                                                                                                                                               |
| innodb_fill_factor                                       | 100                                                                                                                                                                                                                                                                                                                                                                                                              |
| innodb_flush_log_at_timeout                              | 1                                                                                                                                                                                                                                                                                                                                                                                                                |
| innodb_flush_log_at_trx_commit                           | 1                                                                                                                                                                                                                                                                                                                                                                                                                |
| innodb_flush_method                                      |                                                                                                                                                                                                                                                                                                                                                                                                                  |
| innodb_flush_neighbors                                   | 1                                                                                                                                                                                                                                                                                                                                                                                                                |
| innodb_flush_sync                                        | ON                                                                                                                                                                                                                                                                                                                                                                                                               |
| innodb_flushing_avg_loops                                | 30                                                                                                                                                                                                                                                                                                                                                                                                               |
| innodb_force_load_corrupted                              | OFF                                                                                                                                                                                                                                                                                                                                                                                                              |
| innodb_force_recovery                                    | 0                                                                                                                                                                                                                                                                                                                                                                                                                |
| innodb_ft_aux_table                                      |                                                                                                                                                                                                                                                                                                                                                                                                                  |
| innodb_ft_cache_size                                     | 8000000                                                                                                                                                                                                                                                                                                                                                                                                          |
| innodb_ft_enable_diag_print                              | OFF                                                                                                                                                                                                                                                                                                                                                                                                              |
| innodb_ft_enable_stopword                                | ON                                                                                                                                                                                                                                                                                                                                                                                                               |
| innodb_ft_max_token_size                                 | 84                                                                                                                                                                                                                                                                                                                                                                                                               |
| innodb_ft_min_token_size                                 | 3                                                                                                                                                                                                                                                                                                                                                                                                                |
| innodb_ft_num_word_optimize                              | 2000                                                                                                                                                                                                                                                                                                                                                                                                             |
| innodb_ft_result_cache_limit                             | 2000000000                                                                                                                                                                                                                                                                                                                                                                                                       |
| innodb_ft_server_stopword_table                          |                                                                                                                                                                                                                                                                                                                                                                                                                  |
| innodb_ft_sort_pll_degree                                | 2                                                                                                                                                                                                                                                                                                                                                                                                                |
| innodb_ft_total_cache_size                               | 640000000                                                                                                                                                                                                                                                                                                                                                                                                        |
| innodb_ft_user_stopword_table                            |                                                                                                                                                                                                                                                                                                                                                                                                                  |
| innodb_io_capacity                                       | 200                                                                                                                                                                                                                                                                                                                                                                                                              |
| innodb_io_capacity_max                                   | 2000                                                                                                                                                                                                                                                                                                                                                                                                             |
| innodb_large_prefix                                      | ON                                                                                                                                                                                                                                                                                                                                                                                                               |
| innodb_lock_wait_timeout                                 | 50                                                                                                                                                                                                                                                                                                                                                                                                               |
| innodb_locks_unsafe_for_binlog                           | OFF                                                                                                                                                                                                                                                                                                                                                                                                              |
| innodb_log_buffer_size                                   | 16777216                                                                                                                                                                                                                                                                                                                                                                                                         |
| innodb_log_checksums                                     | ON                                                                                                                                                                                                                                                                                                                                                                                                               |
| innodb_log_compressed_pages                              | ON                                                                                                                                                                                                                                                                                                                                                                                                               |
| innodb_log_file_size                                     | 50331648                                                                                                                                                                                                                                                                                                                                                                                                         |
| innodb_log_files_in_group                                | 2                                                                                                                                                                                                                                                                                                                                                                                                                |
| innodb_log_group_home_dir                                | .\                                                                                                                                                                                                                                                                                                                                                                                                               |
| innodb_log_write_ahead_size                              | 8192                                                                                                                                                                                                                                                                                                                                                                                                             |
| innodb_lru_scan_depth                                    | 1024                                                                                                                                                                                                                                                                                                                                                                                                             |
| innodb_max_dirty_pages_pct                               | 75.000000                                                                                                                                                                                                                                                                                                                                                                                                        |
| innodb_max_dirty_pages_pct_lwm                           | 0.000000                                                                                                                                                                                                                                                                                                                                                                                                         |
| innodb_max_purge_lag                                     | 0                                                                                                                                                                                                                                                                                                                                                                                                                |
| innodb_max_purge_lag_delay                               | 0                                                                                                                                                                                                                                                                                                                                                                                                                |
| innodb_max_undo_log_size                                 | 1073741824                                                                                                                                                                                                                                                                                                                                                                                                       |
| innodb_monitor_disable                                   |                                                                                                                                                                                                                                                                                                                                                                                                                  |
| innodb_monitor_enable                                    |                                                                                                                                                                                                                                                                                                                                                                                                                  |
| innodb_monitor_reset                                     |                                                                                                                                                                                                                                                                                                                                                                                                                  |
| innodb_monitor_reset_all                                 |                                                                                                                                                                                                                                                                                                                                                                                                                  |
| innodb_old_blocks_pct                                    | 37                                                                                                                                                                                                                                                                                                                                                                                                               |
| innodb_old_blocks_time                                   | 1000                                                                                                                                                                                                                                                                                                                                                                                                             |
| innodb_online_alter_log_max_size                         | 134217728                                                                                                                                                                                                                                                                                                                                                                                                        |
| innodb_open_files                                        | 2000                                                                                                                                                                                                                                                                                                                                                                                                             |
| innodb_optimize_fulltext_only                            | OFF                                                                                                                                                                                                                                                                                                                                                                                                              |
| innodb_page_cleaners                                     | 1                                                                                                                                                                                                                                                                                                                                                                                                                |
| innodb_page_size                                         | 16384                                                                                                                                                                                                                                                                                                                                                                                                            |
| innodb_print_all_deadlocks                               | OFF                                                                                                                                                                                                                                                                                                                                                                                                              |
| innodb_purge_batch_size                                  | 300                                                                                                                                                                                                                                                                                                                                                                                                              |
| innodb_purge_rseg_truncate_frequency                     | 128                                                                                                                                                                                                                                                                                                                                                                                                              |
| innodb_purge_threads                                     | 4                                                                                                                                                                                                                                                                                                                                                                                                                |
| innodb_random_read_ahead                                 | OFF                                                                                                                                                                                                                                                                                                                                                                                                              |
| innodb_read_ahead_threshold                              | 56                                                                                                                                                                                                                                                                                                                                                                                                               |
| innodb_read_io_threads                                   | 4                                                                                                                                                                                                                                                                                                                                                                                                                |
| innodb_read_only                                         | OFF                                                                                                                                                                                                                                                                                                                                                                                                              |
| innodb_replication_delay                                 | 0                                                                                                                                                                                                                                                                                                                                                                                                                |
| innodb_rollback_on_timeout                               | OFF                                                                                                                                                                                                                                                                                                                                                                                                              |
| innodb_rollback_segments                                 | 128                                                                                                                                                                                                                                                                                                                                                                                                              |
| innodb_sort_buffer_size                                  | 1048576                                                                                                                                                                                                                                                                                                                                                                                                          |
| innodb_spin_wait_delay                                   | 6                                                                                                                                                                                                                                                                                                                                                                                                                |
| innodb_stats_auto_recalc                                 | ON                                                                                                                                                                                                                                                                                                                                                                                                               |
| innodb_stats_include_delete_marked                       | OFF                                                                                                                                                                                                                                                                                                                                                                                                              |
| innodb_stats_method                                      | nulls_equal                                                                                                                                                                                                                                                                                                                                                                                                      |
| innodb_stats_on_metadata                                 | OFF                                                                                                                                                                                                                                                                                                                                                                                                              |
| innodb_stats_persistent                                  | ON                                                                                                                                                                                                                                                                                                                                                                                                               |
| innodb_stats_persistent_sample_pages                     | 20                                                                                                                                                                                                                                                                                                                                                                                                               |
| innodb_stats_sample_pages                                | 8                                                                                                                                                                                                                                                                                                                                                                                                                |
| innodb_stats_transient_sample_pages                      | 8                                                                                                                                                                                                                                                                                                                                                                                                                |
| innodb_status_output                                     | ON                                                                                                                                                                                                                                                                                                                                                                                                               |
| innodb_status_output_locks                               | ON                                                                                                                                                                                                                                                                                                                                                                                                               |
| innodb_strict_mode                                       | ON                                                                                                                                                                                                                                                                                                                                                                                                               |
| innodb_support_xa                                        | ON                                                                                                                                                                                                                                                                                                                                                                                                               |
| innodb_sync_array_size                                   | 1                                                                                                                                                                                                                                                                                                                                                                                                                |
| innodb_sync_spin_loops                                   | 30                                                                                                                                                                                                                                                                                                                                                                                                               |
| innodb_table_locks                                       | ON                                                                                                                                                                                                                                                                                                                                                                                                               |
| innodb_temp_data_file_path                               | ibtmp1:12M:autoextend                                                                                                                                                                                                                                                                                                                                                                                            |
| innodb_thread_concurrency                                | 0                                                                                                                                                                                                                                                                                                                                                                                                                |
| innodb_thread_sleep_delay                                | 10000                                                                                                                                                                                                                                                                                                                                                                                                            |
| innodb_tmpdir                                            |                                                                                                                                                                                                                                                                                                                                                                                                                  |
| innodb_undo_directory                                    | .\                                                                                                                                                                                                                                                                                                                                                                                                               |
| innodb_undo_log_truncate                                 | OFF                                                                                                                                                                                                                                                                                                                                                                                                              |
| innodb_undo_logs                                         | 128                                                                                                                                                                                                                                                                                                                                                                                                              |
| innodb_undo_tablespaces                                  | 0                                                                                                                                                                                                                                                                                                                                                                                                                |
| innodb_use_native_aio                                    | ON                                                                                                                                                                                                                                                                                                                                                                                                               |
| innodb_version                                           | 5.7.25                                                                                                                                                                                                                                                                                                                                                                                                           |
| innodb_write_io_threads                                  | 4                                                                                                                                                                                                                                                                                                                                                                                                                |
| insert_id                                                | 0                                                                                                                                                                                                                                                                                                                                                                                                                |
| interactive_timeout                                      | 28800                                                                                                                                                                                                                                                                                                                                                                                                            |
| internal_tmp_disk_storage_engine                         | InnoDB                                                                                                                                                                                                                                                                                                                                                                                                           |
| join_buffer_size                                         | 262144                                                                                                                                                                                                                                                                                                                                                                                                           |
| keep_files_on_create                                     | OFF                                                                                                                                                                                                                                                                                                                                                                                                              |
| key_buffer_size                                          | 8388608                                                                                                                                                                                                                                                                                                                                                                                                          |
| key_cache_age_threshold                                  | 300                                                                                                                                                                                                                                                                                                                                                                                                              |
| key_cache_block_size                                     | 1024                                                                                                                                                                                                                                                                                                                                                                                                             |
| key_cache_division_limit                                 | 100                                                                                                                                                                                                                                                                                                                                                                                                              |
| keyring_operations                                       | ON                                                                                                                                                                                                                                                                                                                                                                                                               |
| large_files_support                                      | ON                                                                                                                                                                                                                                                                                                                                                                                                               |
| large_page_size                                          | 0                                                                                                                                                                                                                                                                                                                                                                                                                |
| large_pages                                              | OFF                                                                                                                                                                                                                                                                                                                                                                                                              |
| last_insert_id                                           | 0                                                                                                                                                                                                                                                                                                                                                                                                                |
| lc_messages                                              | en_US                                                                                                                                                                                                                                                                                                                                                                                                            |
| lc_messages_dir                                          | D:\installsoft\MySQL\mysql-5.7.25-winx64\share\                                                                                                                                                                                                                                                                                                                                                                  |
| lc_time_names                                            | en_US                                                                                                                                                                                                                                                                                                                                                                                                            |
| license                                                  | GPL                                                                                                                                                                                                                                                                                                                                                                                                              |
| local_infile                                             | ON                                                                                                                                                                                                                                                                                                                                                                                                               |
| lock_wait_timeout                                        | 31536000                                                                                                                                                                                                                                                                                                                                                                                                         |
| log_bin                                                  | ON                                                                                                                                                                                                                                                                                                                                                                                                               |
| log_bin_basename                                         | D:\installsoft\MySQL\mysql-5.7.25-winx64\data\mysql_bin                                                                                                                                                                                                                                                                                                                                                          |
| log_bin_index                                            | D:\installsoft\MySQL\mysql-5.7.25-winx64\data\mysql_bin.index                                                                                                                                                                                                                                                                                                                                                    |
| log_bin_trust_function_creators                          | OFF                                                                                                                                                                                                                                                                                                                                                                                                              |
| log_bin_use_v1_row_events                                | OFF                                                                                                                                                                                                                                                                                                                                                                                                              |
| log_builtin_as_identified_by_password                    | OFF                                                                                                                                                                                                                                                                                                                                                                                                              |
| log_error                                                | D:\installsoft\MySQL\mysql-5.7.25-winx64\data\DESKTOP-3OB6NA3.err                                                                                                                                                                                                                                                                                                                                                |
| log_error_verbosity                                      | 3                                                                                                                                                                                                                                                                                                                                                                                                                |
| log_output                                               | FILE                                                                                                                                                                                                                                                                                                                                                                                                             |
| log_queries_not_using_indexes                            | OFF                                                                                                                                                                                                                                                                                                                                                                                                              |
| log_slave_updates                                        | OFF                                                                                                                                                                                                                                                                                                                                                                                                              |
| log_slow_admin_statements                                | OFF                                                                                                                                                                                                                                                                                                                                                                                                              |
| log_slow_slave_statements                                | OFF                                                                                                                                                                                                                                                                                                                                                                                                              |
| log_statements_unsafe_for_binlog                         | ON                                                                                                                                                                                                                                                                                                                                                                                                               |
| log_syslog                                               | ON                                                                                                                                                                                                                                                                                                                                                                                                               |
| log_syslog_tag                                           |                                                                                                                                                                                                                                                                                                                                                                                                                  |
| log_throttle_queries_not_using_indexes                   | 0                                                                                                                                                                                                                                                                                                                                                                                                                |
| log_timestamps                                           | UTC                                                                                                                                                                                                                                                                                                                                                                                                              |
| log_warnings                                             | 2                                                                                                                                                                                                                                                                                                                                                                                                                |
| long_query_time                                          | 0.000000                                                                                                                                                                                                                                                                                                                                                                                                         |
| low_priority_updates                                     | OFF                                                                                                                                                                                                                                                                                                                                                                                                              |
| lower_case_file_system                                   | ON                                                                                                                                                                                                                                                                                                                                                                                                               |
| lower_case_table_names                                   | 1                                                                                                                                                                                                                                                                                                                                                                                                                |
| master_info_repository                                   | FILE                                                                                                                                                                                                                                                                                                                                                                                                             |
| master_verify_checksum                                   | OFF                                                                                                                                                                                                                                                                                                                                                                                                              |
| max_allowed_packet                                       | 4194304                                                                                                                                                                                                                                                                                                                                                                                                          |
| max_binlog_cache_size                                    | 18446744073709547520                                                                                                                                                                                                                                                                                                                                                                                             |
| max_binlog_size                                          | 1073741824                                                                                                                                                                                                                                                                                                                                                                                                       |
| max_binlog_stmt_cache_size                               | 18446744073709547520                                                                                                                                                                                                                                                                                                                                                                                             |
| max_connect_errors                                       | 100                                                                                                                                                                                                                                                                                                                                                                                                              |
| max_connections                                          | 200                                                                                                                                                                                                                                                                                                                                                                                                              |
| max_delayed_threads                                      | 20                                                                                                                                                                                                                                                                                                                                                                                                               |
| max_digest_length                                        | 1024                                                                                                                                                                                                                                                                                                                                                                                                             |
| max_error_count                                          | 64                                                                                                                                                                                                                                                                                                                                                                                                               |
| max_execution_time                                       | 0                                                                                                                                                                                                                                                                                                                                                                                                                |
| max_heap_table_size                                      | 16777216                                                                                                                                                                                                                                                                                                                                                                                                         |
| max_insert_delayed_threads                               | 20                                                                                                                                                                                                                                                                                                                                                                                                               |
| max_join_size                                            | 18446744073709551615                                                                                                                                                                                                                                                                                                                                                                                             |
| max_length_for_sort_data                                 | 1024                                                                                                                                                                                                                                                                                                                                                                                                             |
| max_points_in_geometry                                   | 65536                                                                                                                                                                                                                                                                                                                                                                                                            |
| max_prepared_stmt_count                                  | 16382                                                                                                                                                                                                                                                                                                                                                                                                            |
| max_relay_log_size                                       | 0                                                                                                                                                                                                                                                                                                                                                                                                                |
| max_seeks_for_key                                        | 4294967295                                                                                                                                                                                                                                                                                                                                                                                                       |
| max_sort_length                                          | 1024                                                                                                                                                                                                                                                                                                                                                                                                             |
| max_sp_recursion_depth                                   | 0                                                                                                                                                                                                                                                                                                                                                                                                                |
| max_tmp_tables                                           | 32                                                                                                                                                                                                                                                                                                                                                                                                               |
| max_user_connections                                     | 0                                                                                                                                                                                                                                                                                                                                                                                                                |
| max_write_lock_count                                     | 4294967295                                                                                                                                                                                                                                                                                                                                                                                                       |
| metadata_locks_cache_size                                | 1024                                                                                                                                                                                                                                                                                                                                                                                                             |
| metadata_locks_hash_instances                            | 8                                                                                                                                                                                                                                                                                                                                                                                                                |
| min_examined_row_limit                                   | 0                                                                                                                                                                                                                                                                                                                                                                                                                |
| multi_range_count                                        | 256                                                                                                                                                                                                                                                                                                                                                                                                              |
| myisam_data_pointer_size                                 | 6                                                                                                                                                                                                                                                                                                                                                                                                                |
| myisam_max_sort_file_size                                | 2146435072                                                                                                                                                                                                                                                                                                                                                                                                       |
| myisam_mmap_size                                         | 18446744073709551615                                                                                                                                                                                                                                                                                                                                                                                             |
| myisam_recover_options                                   | OFF                                                                                                                                                                                                                                                                                                                                                                                                              |
| myisam_repair_threads                                    | 1                                                                                                                                                                                                                                                                                                                                                                                                                |
| myisam_sort_buffer_size                                  | 8388608                                                                                                                                                                                                                                                                                                                                                                                                          |
| myisam_stats_method                                      | nulls_unequal                                                                                                                                                                                                                                                                                                                                                                                                    |
| myisam_use_mmap                                          | OFF                                                                                                                                                                                                                                                                                                                                                                                                              |
| mysql_native_password_proxy_users                        | OFF                                                                                                                                                                                                                                                                                                                                                                                                              |
| named_pipe                                               | OFF                                                                                                                                                                                                                                                                                                                                                                                                              |
| named_pipe_full_access_group                             | *everyone*                                                                                                                                                                                                                                                                                                                                                                                                       |
| net_buffer_length                                        | 16384                                                                                                                                                                                                                                                                                                                                                                                                            |
| net_read_timeout                                         | 30                                                                                                                                                                                                                                                                                                                                                                                                               |
| net_retry_count                                          | 10                                                                                                                                                                                                                                                                                                                                                                                                               |
| net_write_timeout                                        | 60                                                                                                                                                                                                                                                                                                                                                                                                               |
| new                                                      | OFF                                                                                                                                                                                                                                                                                                                                                                                                              |
| ngram_token_size                                         | 2                                                                                                                                                                                                                                                                                                                                                                                                                |
| offline_mode                                             | OFF                                                                                                                                                                                                                                                                                                                                                                                                              |
| old                                                      | OFF                                                                                                                                                                                                                                                                                                                                                                                                              |
| old_alter_table                                          | OFF                                                                                                                                                                                                                                                                                                                                                                                                              |
| old_passwords                                            | 0                                                                                                                                                                                                                                                                                                                                                                                                                |
| open_files_limit                                         | 7048                                                                                                                                                                                                                                                                                                                                                                                                             |
| optimizer_prune_level                                    | 1                                                                                                                                                                                                                                                                                                                                                                                                                |
| optimizer_search_depth                                   | 62                                                                                                                                                                                                                                                                                                                                                                                                               |
| optimizer_switch                                         | index_merge=on,index_merge_union=on,index_merge_sort_union=on,index_merge_intersection=on,engine_condition_pushdown=on,index_condition_pushdown=on,mrr=on,mrr_cost_based=on,block_nested_loop=on,batched_key_access=off,materialization=on,semijoin=on,loosescan=on,firstmatch=on,duplicateweedout=on,subquery_materialization_cost_based=on,use_index_extensions=on,condition_fanout_filter=on,derived_merge=on |
| optimizer_trace                                          | enabled=off,one_line=off                                                                                                                                                                                                                                                                                                                                                                                         |
| optimizer_trace_features                                 | greedy_search=on,range_optimizer=on,dynamic_range=on,repeated_subselect=on                                                                                                                                                                                                                                                                                                                                       |
| optimizer_trace_limit                                    | 1                                                                                                                                                                                                                                                                                                                                                                                                                |
| optimizer_trace_max_mem_size                             | 16384                                                                                                                                                                                                                                                                                                                                                                                                            |
| optimizer_trace_offset                                   | -1                                                                                                                                                                                                                                                                                                                                                                                                               |
| parser_max_mem_size                                      | 18446744073709551615                                                                                                                                                                                                                                                                                                                                                                                             |
| performance_schema                                       | ON                                                                                                                                                                                                                                                                                                                                                                                                               |
| performance_schema_accounts_size                         | -1                                                                                                                                                                                                                                                                                                                                                                                                               |
| performance_schema_digests_size                          | 10000                                                                                                                                                                                                                                                                                                                                                                                                            |
| performance_schema_events_stages_history_long_size       | 10000                                                                                                                                                                                                                                                                                                                                                                                                            |
| performance_schema_events_stages_history_size            | 10                                                                                                                                                                                                                                                                                                                                                                                                               |
| performance_schema_events_statements_history_long_size   | 10000                                                                                                                                                                                                                                                                                                                                                                                                            |
| performance_schema_events_statements_history_size        | 10                                                                                                                                                                                                                                                                                                                                                                                                               |
| performance_schema_events_transactions_history_long_size | 10000                                                                                                                                                                                                                                                                                                                                                                                                            |
| performance_schema_events_transactions_history_size      | 10                                                                                                                                                                                                                                                                                                                                                                                                               |
| performance_schema_events_waits_history_long_size        | 10000                                                                                                                                                                                                                                                                                                                                                                                                            |
| performance_schema_events_waits_history_size             | 10                                                                                                                                                                                                                                                                                                                                                                                                               |
| performance_schema_hosts_size                            | -1                                                                                                                                                                                                                                                                                                                                                                                                               |
| performance_schema_max_cond_classes                      | 80                                                                                                                                                                                                                                                                                                                                                                                                               |
| performance_schema_max_cond_instances                    | -1                                                                                                                                                                                                                                                                                                                                                                                                               |
| performance_schema_max_digest_length                     | 1024                                                                                                                                                                                                                                                                                                                                                                                                             |
| performance_schema_max_file_classes                      | 80                                                                                                                                                                                                                                                                                                                                                                                                               |
| performance_schema_max_file_handles                      | 32768                                                                                                                                                                                                                                                                                                                                                                                                            |
| performance_schema_max_file_instances                    | -1                                                                                                                                                                                                                                                                                                                                                                                                               |
| performance_schema_max_index_stat                        | -1                                                                                                                                                                                                                                                                                                                                                                                                               |
| performance_schema_max_memory_classes                    | 320                                                                                                                                                                                                                                                                                                                                                                                                              |
| performance_schema_max_metadata_locks                    | -1                                                                                                                                                                                                                                                                                                                                                                                                               |
| performance_schema_max_mutex_classes                     | 210                                                                                                                                                                                                                                                                                                                                                                                                              |
| performance_schema_max_mutex_instances                   | -1                                                                                                                                                                                                                                                                                                                                                                                                               |
| performance_schema_max_prepared_statements_instances     | -1                                                                                                                                                                                                                                                                                                                                                                                                               |
| performance_schema_max_program_instances                 | -1                                                                                                                                                                                                                                                                                                                                                                                                               |
| performance_schema_max_rwlock_classes                    | 50                                                                                                                                                                                                                                                                                                                                                                                                               |
| performance_schema_max_rwlock_instances                  | -1                                                                                                                                                                                                                                                                                                                                                                                                               |
| performance_schema_max_socket_classes                    | 10                                                                                                                                                                                                                                                                                                                                                                                                               |
| performance_schema_max_socket_instances                  | -1                                                                                                                                                                                                                                                                                                                                                                                                               |
| performance_schema_max_sql_text_length                   | 1024                                                                                                                                                                                                                                                                                                                                                                                                             |
| performance_schema_max_stage_classes                     | 150                                                                                                                                                                                                                                                                                                                                                                                                              |
| performance_schema_max_statement_classes                 | 193                                                                                                                                                                                                                                                                                                                                                                                                              |
| performance_schema_max_statement_stack                   | 10                                                                                                                                                                                                                                                                                                                                                                                                               |
| performance_schema_max_table_handles                     | -1                                                                                                                                                                                                                                                                                                                                                                                                               |
| performance_schema_max_table_instances                   | -1                                                                                                                                                                                                                                                                                                                                                                                                               |
| performance_schema_max_table_lock_stat                   | -1                                                                                                                                                                                                                                                                                                                                                                                                               |
| performance_schema_max_thread_classes                    | 50                                                                                                                                                                                                                                                                                                                                                                                                               |
| performance_schema_max_thread_instances                  | -1                                                                                                                                                                                                                                                                                                                                                                                                               |
| performance_schema_session_connect_attrs_size            | 512                                                                                                                                                                                                                                                                                                                                                                                                              |
| performance_schema_setup_actors_size                     | -1                                                                                                                                                                                                                                                                                                                                                                                                               |
| performance_schema_setup_objects_size                    | -1                                                                                                                                                                                                                                                                                                                                                                                                               |
| performance_schema_users_size                            | -1                                                                                                                                                                                                                                                                                                                                                                                                               |
| pid_file                                                 | D:\installsoft\MySQL\mysql-5.7.25-winx64\data\DESKTOP-3OB6NA3.pid                                                                                                                                                                                                                                                                                                                                                |
| plugin_dir                                               | D:\installsoft\MySQL\mysql-5.7.25-winx64\lib\plugin\                                                                                                                                                                                                                                                                                                                                                             |
| port                                                     | 3306                                                                                                                                                                                                                                                                                                                                                                                                             |
| preload_buffer_size                                      | 32768                                                                                                                                                                                                                                                                                                                                                                                                            |
| profiling                                                | OFF                                                                                                                                                                                                                                                                                                                                                                                                              |
| profiling_history_size                                   | 15                                                                                                                                                                                                                                                                                                                                                                                                               |
| protocol_version                                         | 10                                                                                                                                                                                                                                                                                                                                                                                                               |
| proxy_user                                               |                                                                                                                                                                                                                                                                                                                                                                                                                  |
| pseudo_slave_mode                                        | OFF                                                                                                                                                                                                                                                                                                                                                                                                              |
| pseudo_thread_id                                         | 2                                                                                                                                                                                                                                                                                                                                                                                                                |
| query_alloc_block_size                                   | 8192                                                                                                                                                                                                                                                                                                                                                                                                             |
| query_cache_limit                                        | 1048576                                                                                                                                                                                                                                                                                                                                                                                                          |
| query_cache_min_res_unit                                 | 4096                                                                                                                                                                                                                                                                                                                                                                                                             |
| query_cache_size                                         | 1048576                                                                                                                                                                                                                                                                                                                                                                                                          |
| query_cache_type                                         | OFF                                                                                                                                                                                                                                                                                                                                                                                                              |
| query_cache_wlock_invalidate                             | OFF                                                                                                                                                                                                                                                                                                                                                                                                              |
| query_prealloc_size                                      | 8192                                                                                                                                                                                                                                                                                                                                                                                                             |
| rand_seed1                                               | 0                                                                                                                                                                                                                                                                                                                                                                                                                |
| rand_seed2                                               | 0                                                                                                                                                                                                                                                                                                                                                                                                                |
| range_alloc_block_size                                   | 4096                                                                                                                                                                                                                                                                                                                                                                                                             |
| range_optimizer_max_mem_size                             | 8388608                                                                                                                                                                                                                                                                                                                                                                                                          |
| rbr_exec_mode                                            | STRICT                                                                                                                                                                                                                                                                                                                                                                                                           |
| read_buffer_size                                         | 131072                                                                                                                                                                                                                                                                                                                                                                                                           |
| read_only                                                | OFF                                                                                                                                                                                                                                                                                                                                                                                                              |
| read_rnd_buffer_size                                     | 262144                                                                                                                                                                                                                                                                                                                                                                                                           |
| relay_log                                                |                                                                                                                                                                                                                                                                                                                                                                                                                  |
| relay_log_basename                                       | D:\installsoft\MySQL\mysql-5.7.25-winx64\data\DESKTOP-3OB6NA3-relay-bin                                                                                                                                                                                                                                                                                                                                          |
| relay_log_index                                          | D:\installsoft\MySQL\mysql-5.7.25-winx64\data\DESKTOP-3OB6NA3-relay-bin.index                                                                                                                                                                                                                                                                                                                                    |
| relay_log_info_file                                      | relay-log.info                                                                                                                                                                                                                                                                                                                                                                                                   |
| relay_log_info_repository                                | FILE                                                                                                                                                                                                                                                                                                                                                                                                             |
| relay_log_purge                                          | ON                                                                                                                                                                                                                                                                                                                                                                                                               |
| relay_log_recovery                                       | OFF                                                                                                                                                                                                                                                                                                                                                                                                              |
| relay_log_space_limit                                    | 0                                                                                                                                                                                                                                                                                                                                                                                                                |
| report_host                                              |                                                                                                                                                                                                                                                                                                                                                                                                                  |
| report_password                                          |                                                                                                                                                                                                                                                                                                                                                                                                                  |
| report_port                                              | 3306                                                                                                                                                                                                                                                                                                                                                                                                             |
| report_user                                              |                                                                                                                                                                                                                                                                                                                                                                                                                  |
| require_secure_transport                                 | OFF                                                                                                                                                                                                                                                                                                                                                                                                              |
| rpl_stop_slave_timeout                                   | 31536000                                                                                                                                                                                                                                                                                                                                                                                                         |
| secure_auth                                              | ON                                                                                                                                                                                                                                                                                                                                                                                                               |
| secure_file_priv                                         | NULL                                                                                                                                                                                                                                                                                                                                                                                                             |
| server_id                                                | 1                                                                                                                                                                                                                                                                                                                                                                                                                |
| server_id_bits                                           | 32                                                                                                                                                                                                                                                                                                                                                                                                               |
| server_uuid                                              | 5535390b-40a4-11e9-af3e-e86a64887726                                                                                                                                                                                                                                                                                                                                                                             |
| session_track_gtids                                      | OFF                                                                                                                                                                                                                                                                                                                                                                                                              |
| session_track_schema                                     | ON                                                                                                                                                                                                                                                                                                                                                                                                               |
| session_track_state_change                               | OFF                                                                                                                                                                                                                                                                                                                                                                                                              |
| session_track_system_variables                           | time_zone,autocommit,character_set_client,character_set_results,character_set_connection                                                                                                                                                                                                                                                                                                                         |
| session_track_transaction_info                           | OFF                                                                                                                                                                                                                                                                                                                                                                                                              |
| sha256_password_proxy_users                              | OFF                                                                                                                                                                                                                                                                                                                                                                                                              |
| shared_memory                                            | OFF                                                                                                                                                                                                                                                                                                                                                                                                              |
| shared_memory_base_name                                  | MYSQL                                                                                                                                                                                                                                                                                                                                                                                                            |
| show_compatibility_56                                    | OFF                                                                                                                                                                                                                                                                                                                                                                                                              |
| show_create_table_verbosity                              | OFF                                                                                                                                                                                                                                                                                                                                                                                                              |
| show_old_temporals                                       | OFF                                                                                                                                                                                                                                                                                                                                                                                                              |
| skip_external_locking                                    | ON                                                                                                                                                                                                                                                                                                                                                                                                               |
| skip_name_resolve                                        | OFF                                                                                                                                                                                                                                                                                                                                                                                                              |
| skip_networking                                          | OFF                                                                                                                                                                                                                                                                                                                                                                                                              |
| skip_show_database                                       | OFF                                                                                                                                                                                                                                                                                                                                                                                                              |
| slave_allow_batching                                     | OFF                                                                                                                                                                                                                                                                                                                                                                                                              |
| slave_checkpoint_group                                   | 512                                                                                                                                                                                                                                                                                                                                                                                                              |
| slave_checkpoint_period                                  | 300                                                                                                                                                                                                                                                                                                                                                                                                              |
| slave_compressed_protocol                                | OFF                                                                                                                                                                                                                                                                                                                                                                                                              |
| slave_exec_mode                                          | STRICT                                                                                                                                                                                                                                                                                                                                                                                                           |
| slave_load_tmpdir                                        | C:\Windows\TEMP                                                                                                                                                                                                                                                                                                                                                                                                  |
| slave_max_allowed_packet                                 | 1073741824                                                                                                                                                                                                                                                                                                                                                                                                       |
| slave_net_timeout                                        | 60                                                                                                                                                                                                                                                                                                                                                                                                               |
| slave_parallel_type                                      | DATABASE                                                                                                                                                                                                                                                                                                                                                                                                         |
| slave_parallel_workers                                   | 0                                                                                                                                                                                                                                                                                                                                                                                                                |
| slave_pending_jobs_size_max                              | 16777216                                                                                                                                                                                                                                                                                                                                                                                                         |
| slave_preserve_commit_order                              | OFF                                                                                                                                                                                                                                                                                                                                                                                                              |
| slave_rows_search_algorithms                             | TABLE_SCAN,INDEX_SCAN                                                                                                                                                                                                                                                                                                                                                                                            |
| slave_skip_errors                                        | OFF                                                                                                                                                                                                                                                                                                                                                                                                              |
| slave_sql_verify_checksum                                | ON                                                                                                                                                                                                                                                                                                                                                                                                               |
| slave_transaction_retries                                | 10                                                                                                                                                                                                                                                                                                                                                                                                               |
| slave_type_conversions                                   |                                                                                                                                                                                                                                                                                                                                                                                                                  |
| slow_launch_time                                         | 2                                                                                                                                                                                                                                                                                                                                                                                                                |
| slow_query_log                                           | ON                                                                                                                                                                                                                                                                                                                                                                                                               |
| slow_query_log_file                                      | D:/installsoft/MySQL/mysql-5.7.25-winx64/log/slow.log                                                                                                                                                                                                                                                                                                                                                            |
| socket                                                   | MySQL                                                                                                                                                                                                                                                                                                                                                                                                            |
| sort_buffer_size                                         | 262144                                                                                                                                                                                                                                                                                                                                                                                                           |
| sql_auto_is_null                                         | OFF                                                                                                                                                                                                                                                                                                                                                                                                              |
| sql_big_selects                                          | ON                                                                                                                                                                                                                                                                                                                                                                                                               |
| sql_buffer_result                                        | OFF                                                                                                                                                                                                                                                                                                                                                                                                              |
| sql_log_bin                                              | ON                                                                                                                                                                                                                                                                                                                                                                                                               |
| sql_log_off                                              | OFF                                                                                                                                                                                                                                                                                                                                                                                                              |
| sql_mode                                                 | ONLY_FULL_GROUP_BY,STRICT_TRANS_TABLES,NO_ZERO_IN_DATE,NO_ZERO_DATE,ERROR_FOR_DIVISION_BY_ZERO,NO_AUTO_CREATE_USER,NO_ENGINE_SUBSTITUTION                                                                                                                                                                                                                                                                        |
| sql_notes                                                | ON                                                                                                                                                                                                                                                                                                                                                                                                               |
| sql_quote_show_create                                    | ON                                                                                                                                                                                                                                                                                                                                                                                                               |
| sql_safe_updates                                         | OFF                                                                                                                                                                                                                                                                                                                                                                                                              |
| sql_select_limit                                         | 18446744073709551615                                                                                                                                                                                                                                                                                                                                                                                             |
| sql_slave_skip_counter                                   | 0                                                                                                                                                                                                                                                                                                                                                                                                                |
| sql_warnings                                             | OFF                                                                                                                                                                                                                                                                                                                                                                                                              |
| ssl_ca                                                   |                                                                                                                                                                                                                                                                                                                                                                                                                  |
| ssl_capath                                               |                                                                                                                                                                                                                                                                                                                                                                                                                  |
| ssl_cert                                                 |                                                                                                                                                                                                                                                                                                                                                                                                                  |
| ssl_cipher                                               |                                                                                                                                                                                                                                                                                                                                                                                                                  |
| ssl_crl                                                  |                                                                                                                                                                                                                                                                                                                                                                                                                  |
| ssl_crlpath                                              |                                                                                                                                                                                                                                                                                                                                                                                                                  |
| ssl_key                                                  |                                                                                                                                                                                                                                                                                                                                                                                                                  |
| stored_program_cache                                     | 256                                                                                                                                                                                                                                                                                                                                                                                                              |
| super_read_only                                          | OFF                                                                                                                                                                                                                                                                                                                                                                                                              |
| sync_binlog                                              | 1                                                                                                                                                                                                                                                                                                                                                                                                                |
| sync_frm                                                 | ON                                                                                                                                                                                                                                                                                                                                                                                                               |
| sync_master_info                                         | 10000                                                                                                                                                                                                                                                                                                                                                                                                            |
| sync_relay_log                                           | 10000                                                                                                                                                                                                                                                                                                                                                                                                            |
| sync_relay_log_info                                      | 10000                                                                                                                                                                                                                                                                                                                                                                                                            |
| system_time_zone                                         |                                                                                                                                                                                                                                                                                                                                                                                                                  |
| table_definition_cache                                   | 1400                                                                                                                                                                                                                                                                                                                                                                                                             |
| table_open_cache                                         | 2000                                                                                                                                                                                                                                                                                                                                                                                                             |
| table_open_cache_instances                               | 16                                                                                                                                                                                                                                                                                                                                                                                                               |
| thread_cache_size                                        | 10                                                                                                                                                                                                                                                                                                                                                                                                               |
| thread_handling                                          | one-thread-per-connection                                                                                                                                                                                                                                                                                                                                                                                        |
| thread_stack                                             | 262144                                                                                                                                                                                                                                                                                                                                                                                                           |
| time_format                                              | %H:%i:%s                                                                                                                                                                                                                                                                                                                                                                                                         |
| time_zone                                                | SYSTEM                                                                                                                                                                                                                                                                                                                                                                                                           |
| timestamp                                                | 1566971784.132916                                                                                                                                                                                                                                                                                                                                                                                                |
| tls_version                                              | TLSv1,TLSv1.1                                                                                                                                                                                                                                                                                                                                                                                                    |
| tmp_table_size                                           | 16777216                                                                                                                                                                                                                                                                                                                                                                                                         |
| tmpdir                                                   | C:\Windows\TEMP                                                                                                                                                                                                                                                                                                                                                                                                  |
| transaction_alloc_block_size                             | 8192                                                                                                                                                                                                                                                                                                                                                                                                             |
| transaction_allow_batching                               | OFF                                                                                                                                                                                                                                                                                                                                                                                                              |
| transaction_isolation                                    | READ-COMMITTED                                                                                                                                                                                                                                                                                                                                                                                                   |
| transaction_prealloc_size                                | 4096                                                                                                                                                                                                                                                                                                                                                                                                             |
| transaction_read_only                                    | OFF                                                                                                                                                                                                                                                                                                                                                                                                              |
| transaction_write_set_extraction                         | OFF                                                                                                                                                                                                                                                                                                                                                                                                              |
| tx_isolation                                             | READ-COMMITTED                                                                                                                                                                                                                                                                                                                                                                                                   |
| tx_read_only                                             | OFF                                                                                                                                                                                                                                                                                                                                                                                                              |
| unique_checks                                            | ON                                                                                                                                                                                                                                                                                                                                                                                                               |
| updatable_views_with_limit                               | YES                                                                                                                                                                                                                                                                                                                                                                                                              |
| version                                                  | 5.7.25-log                                                                                                                                                                                                                                                                                                                                                                                                       |
| version_comment                                          | MySQL Community Server (GPL)                                                                                                                                                                                                                                                                                                                                                                                     |
| version_compile_machine                                  | x86_64                                                                                                                                                                                                                                                                                                                                                                                                           |
| version_compile_os                                       | Win64                                                                                                                                                                                                                                                                                                                                                                                                            |
| wait_timeout                                             | 28800                                                                                                                                                                                                                                                                                                                                                                                                            |
| warning_count                                            | 0                                                                                                                                                                                                                                                                                                                                                                                                                |
+----------------------------------------------------------+------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------+
513 rows in set, 1 warning (0.00 sec)
```

### 查看某个系统变量：SHOW VARIABLES like '变量名';

## mysql语法规范

1. 不区分大小写，但建议关键字大写，表名、列名小写
2. 每条命令最好用英文分号结尾
3. 每条命令根据需要，可以进行缩进或换行
4. 注释
   - 单行注释：#注释文字
   - 单行注释：-- 注释文字  ，注意， 这里需要加空格
   - 多行注释：/* 注释文字  */

## SQL的语言分类

- **DQL（Data Query Language）**：数据查询语言
  select 相关语句
- **DML（Data Manipulate Language）**：数据操作语言
  insert 、update、delete 语句
- **DDL（Data Define Languge）**：数据定义语言
  create、drop、alter 语句
- **TCL（Transaction Control Language）**：事务控制语言
  set autocommit=0、start transaction、savepoint、commit、rollback

![](https://itsoku.oss-cn-hangzhou.aliyuncs.com/itsoku/blog/article/35/13d1f003-92ed-4c7a-8e1f-0e7e5e66d2ef.png)

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