使用mysql5.5，突然root密码忘记，怎么也登录不了，很急人，该怎么解决呢？下面通过本文给大家介绍mysql5.5忘记root密码的解决办法，需要的朋友参考下吧

方法一：

操作系统：windows操作系统，xp或win7.

C:\Users\Administrator>cd C:\Program Files\MySQL\MySQL Server 5.5\bin
C:\Program Files\MySQL\MySQL Server 5.5\bin>net stop mysql

MySQL 服务正在停止.

MySQL 服务已成功停止。

C:\Program Files\MySQL\MySQL Server 5.5\bin>mysqld --skip-grant-tables

你会看到窗口光标在下一行的第一个位置闪烁，这说明已经启动了，不需要管。

新建一个命令行窗口同样进入到e:\mysql5.5\bin目录，启动mysql

C:\Program Files\MySQL\MySQL Server 5.5\bin>mysqlWelcome to the MySQL monitor. Commands end with ; or \g.Your MySQL connection id is 1Server version: 5.5.36 MySQL Community Server (GPL)Copyright (c) 2000, 2014, Oracle and/or its affiliates. All rights reserved.Oracle is a registered trademark of Oracle Corporation and/or itsaffiliates. Other names may be trademarks of their respectiveowners.Type 'help;' or '\h' for help. Type '\c' to clear the current input statement.mysql> show databases;+--------------------+| Database |+--------------------+| information_schema || mysql || performance_schema || test |+--------------------+4 rows in set (0.00 sec)mysql> use mysql;Database changedmysql> update user set password=PASSWORD('oracle') where user='root';Query OK, 2 rows affected (0.00 sec)Rows matched: 2 Changed: 2 Warnings: 0mysql> flush privileges;Query OK, 0 rows affected (0.01 sec)mysql> quitBye

看看那任务管理器中是否有mysqld.exe进程，如有，kill .

C:\Program Files\MySQL\MySQL Server 5.5\bin>net start mysql

MySQL 服务正在启动 .

MySQL 服务已经启动成功。

C:\Program Files\MySQL\MySQL Server 5.5\bin>mysql -uroot -poracleWelcome to the MySQL monitor. Commands end with ; or \g.Your MySQL connection id is 1Server version: 5.5.36 MySQL Community Server (GPL)Copyright (c) 2000, 2014, Oracle and/or its affiliates. All rights reserved.Oracle is a registered trademark of Oracle Corporation and/or itsaffiliates. Other names may be trademarks of their respectiveowners.Type 'help;' or '\h' for help. Type '\c' to clear the current input statement.mysql>

方法二：

操作系统：windows操作系统，xp或win7.

　　1.dos命令行窗口 进入e:\mysql5.5\bin ,停止mysql 服务

　　e:\mysql5.5\bin>net stop mysql

　　注意:看看那任务管理器中是否有mysqld.exe进程，如有，kill them all.

　　2. 以不检查权限的方式启动mysql

　　e:\mysql5.5\bin>mysqld.exe --skip-grant-tables

　　你会看到窗口光标在下一行的第一个位置闪烁，这说明已经启动了，不需要管。

　　3. 新建一个命令行窗口同样进入到e:\mysql5.5\bin目录，启动mysql

　　e:\mysql5.5\bin>mysql

　　4. 修改root密码

mysql>use mysql　　mysql>update user set password=PASSWORD('new_password') where user='root';　　mysql>flush privileges;　　mysql>quit

　　5. 看看那任务管理器中是否有mysqld.exe进程，如有，kill them all.

　　6. 重启mysql，就可以用你设置新密码登陆

e:\mysql5.5\bin>net start mysql　　e:\mysql5.5\bin>mysql -u root -pnew_password 　　that's all .