MySQL -u root
mysql> SET PASSWORD FOR 'root'@'localhost' = PASSWORD('newpass');
方法2：用mysqladmin
mysqladmin -u root password "newpass"
如果root已經設置過密碼，采用如下方法
mysqladmin -u root password oldpass "newpass"
方法3： 用UPDATE直接編輯user表
mysql -u root
mysql> use mysql;
mysql> UPDATE user SET Password = PASSWORD('newpass') WHERE user = 'root';
mysql> FLUSH PRIVILEGES;
在丟失root密碼的時候，可以這樣
mysqld_safe --skip-grant-tables
mysql -u root mysql
mysql> UPDATE user SET password=PASSWORD("new password") WHERE user='root';
mysql> FLUSH PRIVILEGES;
