MySQL修改root密码的3种方法

用set password命令 

mysql> set password for u<sername>@localhost = password('<newpassword>'); 

用mysqladmin 

mysqladmin -u<sername> -p<oldpassword> password <newpassword> 

例子：

mysqladmin -uroot -p123456 password 12

用update直接编辑user表 

mysql> use mysql; 
mysql> update user set password=password('12') where user='root' and host='localhost'; 
mysql> flush privileges;