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>mysql
Welcome to the MySQL monitor. Commands end with ; or \g.
Your MySQL connection id is 1
Server 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 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> show databases;
+--------------------+
| Database |
+--------------------+
| information_schema |
| mysql |
| performance_schema |
| test |
+--------------------+
4 rows in set (0.00 sec)
mysql> use mysql;
Database changed
mysql> update user set password=PASSWORD('oracle') where user='root';
Query OK, 2 rows affected (0.00 sec)
Rows matched: 2 Changed: 2 Warnings: 0
mysql> flush privileges;
Query OK, 0 rows affected (0.01 sec)
mysql> quit
Bye
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 -poracle Welcome to the MySQL monitor. Commands end with ; or \g. Your MySQL connection id is 1 Server 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 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>
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 .