一、windows下修改MySQL密碼的方法
如果在Windows下忘記了MySQL的密碼，可以這樣做：
1.關閉正在運行的MySQL服務：net stop mysql或 在windows 任務管理器中結束 mysqld.exe 進程或在 管理工具里面的服務找到 mysql服務 ，將其停止；

復制代碼 代碼如下:

C:/Users/Administrator>net stop mysql
MySQL 服務正在停止.
MySQL 服務已成功停止。

復制代碼 代碼如下:

C:/Users/Administrator>cd C:/Program Files/MySQL/MySQL Server 5.5/bin

C:/Program Files/MySQL/MySQL Server 5.5/bin>

復制代碼 代碼如下:

C:/Program Files/MySQL/MySQL Server 5.5/bin>mysqld -nt --skip-grant-tables
140317 13:23:11 [Warning] option 'new': boolean value 't' wasn't recognized. Set
 to OFF.

復制代碼 代碼如下:

C:/Users/Administrator>cd C:/Program Files/MySQL/MySQL Server 5.5/bin

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: 5.5.35 MySQL Community Server (GPL)

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>

復制代碼 代碼如下:

mysql>USE mysql;

復制代碼 代碼如下:

UPDATE user SET password=PASSWORD("123456") WHERE user="root";

復制代碼 代碼如下:

mysql>FLUSH PRIVILEGES;

二、更改mysql密碼常用的三種方法
大部分情況下，一般用戶沒有權限更改密碼，只有申請了權限或root用戶才可以更改密碼；
1.方法1：用mysqladmin

復制代碼 代碼如下:

mysqladmin -u root password "123456";

復制代碼 代碼如下:

mysqladmin -u root password -p "123456";

復制代碼 代碼如下:

mysql -u root -p
mysql> SET PASSWORD FOR 'root'@'localhost' = PASSWORD('123456');

復制代碼 代碼如下:

mysql> USE mysql;
mysql> UPDATE user SET Password = PASSWORD('123456') WHERE user='root';