MySQL忘记密码,重置密码,mysql.user表为空的解决办法

一、用户表有用户,直接修改密码

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ERROR 1045 (28000): Access denied for user 'root'@'localhost' (using password: YES)

修改mysql配置文件my.cnf:

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vim /etc/my.cnf

在[mysqld]中添加:

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skip-grant-tables

重启mysql服务,用空密码直接登录,查询用户表,有结果则按如下步骤修改,结果为空直接最后的解决办法

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mysql> select Host,User,authentication_string from mysql.user;
+-----------+---------------+-------------------------------------------+
| Host | User | authentication_string |
+-----------+---------------+-------------------------------------------+
| localhost | root | *6A7A490FB9DC8C33C2B025A91737077A7E9CC5E5 |
| localhost | mysql.session | *THISISNOTAVALIDPASSWORDTHATCANBEUSEDHERE |
| localhost | mysql.sys | *THISISNOTAVALIDPASSWORDTHATCANBEUSEDHERE |
| % | root | *6A7A490FB9DC8C33C2B025A91737077A7E9CC5E5 |
+-----------+---------------+-------------------------------------------+
4 rows in set (0.00 sec)

修改对应用户的密码

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# 重置密码为 123456
mysql> update mysql.user set authentication_string=password('123456') where user='root'
Query OK, 2 rows affected, 1 warning (0.00 sec)
Rows matched: 2 Changed: 2 Warnings: 1

# 刷新权限,使配置生效
mysql> FLUSH PRIVILEGES;
Query OK, 0 rows affected (0.00 sec)

# 退出
mysql> quit
Bye

取消或注释掉my.cnf配置文件添加的选项 skip-grant-tables ,重启mysql服务,搞定收工。

二、用户表没有数据,则需要插入用户数据

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mysql> select Host,User,authentication_string from mysql.user;
Empty set (0.00 sec)
# 退出登陆
mysql> exit
Bye

编辑my.cnf配置文件,添加或修改下面两项(我这没有sql_mode项):

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sql_mode=NO_ENGINE_SUBSTITUTION
skip-grant-tables

1、停止mysql服务,启动数据库的安全模式:mysqld_safe &

2、使用root 空密码连接数据库: mysql -uroot -p

插入root用户数据

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mysql> insert into mysql.user(Host,User,authentication_string) values("%","root",password("123456")); 
Query OK, 1 row affected, 4 warnings (0.00 sec)

再次查询mysql.user表,会报错

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mysql> select Host,User,authentication_string from mysql.user;
ERROR 1194 (HY000): Table 'user' is marked as crashed and should be repaired

需要修复mysql.user表

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mysql> REPAIR TABLE mysql.user;
+------------+--------+----------+-------------------------------------------------+
| Table | Op | Msg_type | Msg_text |
+------------+--------+----------+-------------------------------------------------+
| mysql.user | repair | info | Wrong bytesec: 113-108- 95 at 396; Skipped |
| mysql.user | repair | info | Found block that points outside data file at 32 |
| mysql.user | repair | info | Found block that points outside data file at 36 |
| mysql.user | repair | info | Found block that points outside data file at 40 |
| mysql.user | repair | info | Found block that points outside data file at 44 |
| mysql.user | repair | info | Found block that points outside data file at 48 |
| mysql.user | repair | info | Found block that points outside data file at 52 |
| mysql.user | repair | info | Found block that points outside data file at 56 |
| mysql.user | repair | info | Found block that points outside data file at 60 |
| mysql.user | repair | warning | Number of rows changed from 4 to 3 |
| mysql.user | repair | status | OK |
+------------+--------+----------+-------------------------------------------------+
11 rows in set (0.64 sec)

# 再次查询user表
mysql> select Host,User,authentication_string from mysql.user;
+-----------+---------------+-------------------------------------------+
| Host | User | authentication_string |
+-----------+---------------+-------------------------------------------+
| localhost | mysql.session | *THISISNOTAVALIDPASSWORDTHATCANBEUSEDHERE |
| localhost | mysql.sys | *THISISNOTAVALIDPASSWORDTHATCANBEUSEDHERE |
| % | root | *6BB4837EB74329105EE4568DDA7DC67ED2CA2AD9 |
+-----------+---------------+-------------------------------------------+
3 rows in set (0.00 sec)

修改root用户的权限:

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  update mysql.user set
`Select_priv` = 'Y',
`Insert_priv` = 'Y',
`Update_priv` = 'Y',
`Delete_priv` = 'Y',
`Create_priv` = 'Y',
`Drop_priv` = 'Y',
`Reload_priv` = 'Y',
`Shutdown_priv` = 'Y',
`Process_priv` = 'Y',
`File_priv` = 'Y',
`Grant_priv` = 'Y',
`References_priv` = 'Y',
`Index_priv` = 'Y',
`Alter_priv` = 'Y',
`Show_db_priv` = 'Y',
`Super_priv` = 'Y',
`Create_tmp_table_priv` = 'Y',
`Lock_tables_priv` = 'Y',
`Execute_priv` = 'Y',
`Repl_slave_priv` = 'Y',
`Repl_client_priv` = 'Y',
`Create_view_priv` = 'Y',
`Show_view_priv` = 'Y',
`Create_routine_priv` = 'Y',
`Alter_routine_priv` = 'Y',
`Create_user_priv` = 'Y',
`Event_priv` = 'Y',
`Trigger_priv` = 'Y',
`Create_tablespace_priv` = 'Y'
where user='root';
# 更新权限
mysql> flush privileges;
Query OK, 0 rows affected (0.00 sec)
# 退出登陆
mysql> exit
Bye

退出mysql,将my.cnf配置文件的修改恢复

结束mysqld_safe 进程:pkill mysql

启动mysql服务: systemctl start mysql

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