MYSQL密码相关设置方法（以5.1版本为例）

1、mysql设置密码的几种方法
新安装的mysql数据库是没有密码的
[root@localhost ~]# mysql -u root -p
Enter password: ###此处为空，直接回车
Welcome to the MySQL monitor. Commands end with ; or \g.
Your MySQL connection id is 6
Server version: 5.1.73 Source distribution
Copyright (c) 2000, 2013, 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>

设置方法：
一、在用root帐号进入mysql后设置密码
mysql> set password=password('123456'); ###123456为密码
Query OK, 0 rows affected (0.00 sec)

mysql> set password=password(''); ###清除密码，如今为空
Query OK, 0 rows affected (0.00 sec)

mysql> flush privileges;
Query OK, 0 rows affected (0.00 sec) ###刷新，使修改当即生效

二、在mysql外部（操做系统）设置密码
[root@localhost ~]# mysqladmin -u root password '123456' ###此命令是在/usr/bin/mysqladmin中
[root@localhost ~]# whereis mysqladmin
mysqladmin: /usr/bin/mysqladmin

三、登录数据库，切换到数据库后
mysql> use mysql;
Database changed

mysql> UPDATE user SET password=PASSWORD("123456") WHERE user='root'; #大小写可忽略，123456即为设置的密码
Query OK, 3 rows affected (0.00 sec)
Rows matched: 3 Changed: 3 Warnings: 0

mysql> flush privileges;

2、修改密码
一、进入数据库以后修改密码
mysql> use mysql;

mysql> update user set password = password('abcdef') where user = 'root'; ###abcdef为新密码

mysql> flush privileges;

二、在mysql外部（操做系统）修改密码
mysqladmin -u root password oldpass “newpass” 、

3、root密码丢失，恢复root密码
一、关闭mysql
[root@localhost ~]# service mysqld stop
中止 mysqld： [肯定]

二、跳过mysql权限后台启动
[root@localhost ~]# /usr/bin/mysqld_safe --user=mysql --skip-grant-tables &
[1] 31755
[root@localhost ~]# 180406 19:52:45 mysqld_safe Logging to '/var/log/mysqld.log'.
180406 19:52:45 mysqld_safe Starting mysqld daemon with databases from /var/lib/mysql

三、执行mysql命令，进入数据库
[root@localhost ~]# mysql
Welcome to the MySQL monitor. Commands end with ; or \g.
Your MySQL connection id is 1
Server version: 5.1.73 Source distribution

Copyright (c) 2000, 2013, 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>

四、修改密码
mysql> use mysql;

mysql> update user set password=password('123456') where user='root';
Query OK, 2 rows affected (0.00 sec)
Rows matched: 3 Changed: 2 Warnings: 0

五、中止mysql,再以正常方式启动[root@localhost ~]# service mysqld stop180406 19:57:47 mysqld_safe mysqld from pid file /var/run/mysqld/mysqld.pid ended中止 mysqld： [肯定][1]+ Done /usr/bin/mysqld_safe --user=mysql --skip-grant-tables[root@localhost ~]# service mysqld start正在启动 mysqld： [肯定][root@localhost ~]#