MySQL用户管理

创建用户

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语法：CREATE USER user_specification [, user_specification] ...

CREATE USER 'user1'@'192.168.30.74' IDENTIFIED BY 'centos';

user_specification：IDENTIFIED BY [PASSWORD] 'password'

MySQL 的用户信息存放在 mysql 库的 user 表中

SELECT user, host, password FROM user;
+-------+------------------+-------------------------------------------+
| user  | host             | password                                  |
+-------+------------------+-------------------------------------------+
| root  | localhost        | *6F3CAE7C3BBB2A5B5D933738682953BC21AEBEE7 |
| root  | centos75.miariam | *6F3CAE7C3BBB2A5B5D933738682953BC21AEBEE7 |
| root  | 127.0.0.1        | *6F3CAE7C3BBB2A5B5D933738682953BC21AEBEE7 |
| root  | ::1              | *6F3CAE7C3BBB2A5B5D933738682953BC21AEBEE7 |
| user1 | 192.168.30.74    | *128977E278358FF80A246B5046F51043A2B1FCED |
+-------+------------------+-------------------------------------------+
5 rows in set (0.00 sec)

在192.168.30.74的主机上远程登录 MySQL 数据库

mysql -uuser1 -pcentos -h192.168.30.75

查看登录状态

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 使用 SHOW processlist 命令查看用户的进程状态

SHOW processlist;
+----+-------------+---------------------+-------+---------+------+--------------------------+------------------+----------+
| Id | User        | Host                | db    | Command | Time | State                    | Info             | Progress |
+----+-------------+---------------------+-------+---------+------+--------------------------+------------------+----------+
|  1 | system user |                     | NULL  | Daemon  | NULL | InnoDB purge coordinator | NULL             |    0.000 |
|  2 | system user |                     | NULL  | Daemon  | NULL | InnoDB purge worker      | NULL             |    0.000 |
|  4 | system user |                     | NULL  | Daemon  | NULL | InnoDB purge worker      | NULL             |    0.000 |
|  3 | system user |                     | NULL  | Daemon  | NULL | InnoDB purge worker      | NULL             |    0.000 |
|  5 | system user |                     | NULL  | Daemon  | NULL | InnoDB shutdown handler  | NULL             |    0.000 |
| 10 | root        | localhost           | mysql | Query   |    0 | init                     | SHOW processlist |    0.000 |
| 11 | user1       | 192.168.30.74:41820 | NULL  | Sleep   |   58 |                          | NULL             |    0.000 |
+----+-------------+---------------------+-------+---------+------+--------------------------+------------------+----------+
7 rows in set (0.00 sec)

在远程主机上查看登录状态

删除、改名

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• 删除

DROP USER 'user1'@'192.168.30.74';

也可以使用 DELETE 子句对 user 表中的记录进行删除，在删除后使用 FLUSH PRIVILEGES 对数据库的策略进行更新

• 改名

RENAME USER 'user1'@'192.168.30.74' TO 'testuser1'@'192.168.30.74';

修改密码

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语法：SET PASSWORD FOR 'user'@'host' = PASSWORD(‘password'); 

SET PASSWORD FOR 'testuser1'@'192.168.30.74' = PASSWORD('linux');

同样也可以使用 UPDATE 子句对 user 表中的 password 字段进行修改

UPDATE user SET password = password('centos') WHERE user = 'testuser1';

• 破解密码

1. 启动 mysql 前修改 my.cnf 配置文件或者在启动 mysql 进程时使用 --skip-grant-tables 选项来忽略策略表
2. 启动 mysql 进程，使用 UPDATE 子句对 mysql 库中的 user 表的 password 字段进行修改(SET PASSWORD不能使用)
3. 移除步骤一中的选项，重启服务