前言：本文档介绍MYSQL修改用户密码的方法和忘记root密码后的处理方法。
一、三种修改密码的方式
1、修改当前用户的登录密码
脚本：SET PASSWORD=PASSWORD（'netpassword');
例：
mysql> set password=password('root');
Query OK, 0 rows affected (0.00 sec)
2、使用SET修改其他用户的密码，通过ROOT修改其他账号的密码
脚本：SET PASSWORD FOR
'user' @'host'=PASSWORD('newpassword')
例：
mysql> select host,user from mysql.user;
+----------------+--------+
| host | user |
+----------------+--------+
| | test |
| % | john1 |
| % | mytest |
| 127.0.0.1 | root |
| 192.168.189.71 | john |
| 192.168.189.71 | john1 |
| ::1 | john |
| ::1 | root |
| localhost | john |
| localhost | root |
| mysql | root |
+----------------+--------+
11 rows in set (0.00 sec)
mysql> SET PASSWORD FOR
-> 'john1' @'%'=PASSWORD('john');
Query OK, 0 rows affected (0.00 sec)
3、使用UPDATE语句修改其他用户的密码，需要有修改MYSQL权限的用户，一般用ROOT用户
脚本：
UPDATE mysql.user SET
PASSWORD=PASSWORD('newpassword')
WHERE
User='username'
AND
Host='host';
例：
mysql> UPDATE mysql.user SET
-> PASSWORD=PASSWORD('root')
-> where
-> User='root' AND Host='127.0.0.1';
Query OK, 0 rows affected (0.02 sec)
Rows matched: 0 Changed: 0 Warnings: 0
二、忘记ROOT密码的处理方法
1、关闭数据库
脚本：[root@mysql etc]# service mysql stop
2、使用脚本： mysqld_safe --skip-grant-tables 启动数据库
使用/usr/bin/mysqld_safe --skip-grant-tables&启动数据库
3、使用空密码进入数据库（mysql命令后直接回车）
[root@mysql ~]# mysql
Welcome to the MySQL monitor. Commands end with ; or \g.
Your MySQL connection id is 3
Server version: 5.6.20-enterprise-commercial-advanced MySQL Enterprise Server - Advanced Edition (Commercial)
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>
4、使用UPDATE语句修改ROOT密码
mysql> UPDATE mysql.user SET
-> PASSWORD=PASSWORD('root')
-> where
-> User='root' AND Host='localhost';
5、关闭数据库并重新以正常方式启动数据库
[root@mysql ~]# service mysql restart;
Shutting down MySQL.. SUCCESS!
Starting MySQL.. SUCCESS!
[root@mysql ~]# mysql
ERROR 1045 (28000): Access denied for user 'root'@'localhost' (using password: NO)
[root@mysql ~]# mysql -p
Enter password:
Welcome to the MySQL monitor. Commands end with ; or \g.
Your MySQL connection id is 2
Server version: 5.6.20-enterprise-commercial-advanced MySQL Enterprise Server - Advanced Edition (Commercial)
Copyright (c) 2000, 2014, 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>
显示可以成功登录，整个过程很简单。大功告成！！！
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