mysql root 修改密码的多种方法

如果root密码没有丢失

方法1： 用SET PASSWORD命令

　　mysql -u root -p登陆
输入密码：

　　mysql> SET PASSWORD FOR 'root'@'localhost' = PASSWORD('newpass');

方法2：用mysqladmin

如果root已经设置密码：
shell> mysqladmin -u root password oldpass "newpass"   ？？？？有问题

方法3： 用UPDATE直接编辑user表

　　mysql -u root -p
输入密码：

　　mysql> use mysql;

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

　　mysql> FLUSH PRIVILEGES;

如果root密码丢失

在丢失root密码的时候，可以这样

．修改MySQL的登录设置： 
# vi /etc/my.cnf 
在[mysqld]的段中加上一句：skip-grant-tables 
例如： 
[mysqld] 
datadir=/var/lib/mysql 
socket=/var/lib/mysql/mysql.sock 
skip-grant-tables 
保存并且退出vi。 
3．重新启动mysqld 
# /etc/init.d/mysqld restart 
Stopping MySQL: [ OK ] 
Starting MySQL: [ OK ] 
4．登录并修改MySQL的root密码 
# /usr/bin/mysql 
Welcome to the MySQL monitor. Commands end with ; or \g. 
Your MySQL connection id is 3 to server version: 3.23.56 
Type 'help;' or '\h' for help. Type '\c' to clear the buffer. 
mysql> USE mysql ; 
Reading table information for completion of table and column names 
You can turn off this feature to get a quicker startup with -A 
Database changed 
mysql> UPDATE user SET Password = password ( 'new-password' ) WHERE User = 'root' ; 
Query OK, 0 rows affected (0.00 sec) 
Rows matched: 2 Changed: 0 Warnings: 0 
mysql> flush privileges ; 
Query OK, 0 rows affected (0.01 sec) 
mysql> quit 
Bye 

5．将MySQL的登录设置修改回来 
# vi /etc/my.cnf 
将刚才在[mysqld]的段中加上的skip-grant-tables删除 
保存并且退出vi。 

6．重新启动mysqld 
# /etc/init.d/mysqld restart 
Stopping MySQL: [ OK ] 
Starting MySQL: [ OK ]