使用mysql5.5，突然root密碼忘記，怎么也登錄不了，很急人，該怎么解決呢？下面通過本文給大家介紹mysql5.5忘記root密碼的解決辦法，需要的朋友參考下吧
方法一：
操作系統：windows操作系統，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 服務正在停止.
MySQL 服務已成功停止。
C:/Program Files/MySQL/MySQL Server 5.5/bin>mysqld --skip-grant-tables
你會看到窗口光標在下一行的第一個位置閃爍，這說明已經啟動了，不需要管。
新建一個命令行窗口同樣進入到e:/mysql5.5/bin目錄，啟動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 看看那任務管理器中是否有mysqld.exe進程，如有，kill .
C:/Program Files/MySQL/MySQL Server 5.5/bin>net start mysql
MySQL 服務正在啟動 .
MySQL 服務已經啟動成功。
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：
操作系統：windows操作系統，xp或win7.
1.dos命令行窗口 進入e:/mysql5.5/bin ,停止mysql 服務
e:/mysql5.5/bin>net stop mysql
注意:看看那任務管理器中是否有mysqld.exe進程，如有，kill them all.
2. 以不檢查權限的方式啟動mysql
e:/mysql5.5/bin>mysqld.exe --skip-grant-tables
你會看到窗口光標在下一行的第一個位置閃爍，這說明已經啟動了，不需要管。
3. 新建一個命令行窗口同樣進入到e:/mysql5.5/bin目錄，啟動mysql
e:/mysql5.5/bin>mysql
4. 修改root密碼
mysql>use mysql mysql>update user set password=PASSWORD('new_password') where user='root'; mysql>flush privileges; mysql>quit 5. 看看那任務管理器中是否有mysqld.exe進程，如有，kill them all.
6. 重啟mysql，就可以用你設置新密碼登陸
e:/mysql5.5/bin>net start mysql e:/mysql5.5/bin>mysql -u root -pnew_password that's all .
