MySQL 5.7忘记root密码如何修改?

案例环境如下：

        操作系统 ：   centos7

        数据库版本： 5.7.18 MySQL Community Server (GPL)

忘记密码，输入错误的密码时遇到下面错误信息：

[root@mytestlnx02 ~]# mysql -u root -p

Enter password: 

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

[root@mytestlnx02 ~]#

 

检查MySQL服务是否启动，如果启动，关闭MySQL服务

[root@mytestlnx02 ~]# ps -ef | grep -i mysql

root     22972     1  0 14:18 pts/0    00:00:00 /bin/sh /usr/bin/mysqld_safe --datadir=/var/lib/mysql --socket=/var/lib/mysql/mysql.sock --pid-file=/var/run/mysqld/mysqld.pid --basedir=/usr --user=mysql

mysql    23166 22972  0 14:18 pts/0    00:00:00 /usr/sbin/mysqld --basedir=/usr --datadir=/var/lib/mysql --plugin-dir=/usr/lib/mysql/plugin --user=mysql --log-error=/var/log/mysqld.log --pid-file=/var/run/mysqld/mysqld.pid --socket=/var/lib/mysql/mysql.sock

root     23237 21825  0 14:22 pts/0    00:00:00 grep -i mysql

[root@mytestlnx02 ~]# service mysqld stop

Stopping mysqld:  [  OK  ]

[root@mytestlnx02 ~]# 

找到MySQL的my.cnf配置文件，在/etc/my.cnf (有些版本是/etc/mysql/my.cnf）在里面增加下面一段信息：

[mysqld]

skip-grant-tables

然后启动MySQL，进入MySQL后，修改root密码,操作过程中遇到ERROR 1054 (42S22): Unknown column 'password' in 'field list'，查了一下user表的表结构，发现原来MySQL 5.7下，user表已经没有Password字段。加密后的用户密码存储于authentication_string字段。具体操作过程如下所示：

[root@mytestlnx02 ~]# service mysqld start

Starting mysqld:  [  OK  ]

[root@mytestlnx02 ~]# mysql -u root 

Welcome to the MySQL monitor.  Commands end with ; or \g.

Your MySQL connection id is 4

Server version: 5.7.18 MySQL Community Server (GPL)

Copyright (c) 2000, 2017, Oracle and/or its affiliates. All rights reserved.

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> use mysql;

Reading table information for completion of table and column names

You can turn off this feature to get a quicker startup with -A

Database changed

mysql> update user set password=PASSWORD('Kd8k&dfdl023')

    -> where user='root';

ERROR 1054 (42S22): Unknown column 'password' in 'field list'

mysql> update mysql.user set authentication_string=password('Kd8k&dfdl023') where user='root';

Query OK, 1 row affected, 1 warning (0.00 sec)

Rows matched: 1  Changed: 1  Warnings: 1

mysql> flush privileges;

Query OK, 0 rows affected (0.00 sec)

mysql> exit

 

在my.cnf文件中，把刚才加入的那一行“skip-grant-tables”注释或删除掉。 然后重启MySQL服务