创建用户：
mysql> create user 'username'@'ipaddress' identified by 'password'; #注：如果ipaddress为'%'，代表任何地址都可以用新建的用户名连接 mysql> create user 'myroot'@'123.123.12.123' identified by 'mypass'; mysql> create user 'myroot'@'%' identified by 'mypass'; mysql> create user 'myroot'@'%' identified by ''; mysql> create user 'myroot'@'%';创建之后，查询用户权限：
mysql> use mysql; mysql> show grants for myroot@123.123.12.123; +------------------------------------------------+ | Grants for 'myroot'@'123.123.12.123' | +------------------------------------------------+ | GRANT USAGE ON *.* TO 'myroot'@'123.123.12.123' | +------------------------------------------------+授权：
给用户myroot赋予所有数据库的所有权限
mysql> grant all privileges on *.* to 'myroot'@'123.123.12.123' identified by 'mypass' with grant option;给用户myroot赋予数据库db_school的所有权限
mysql> grant all privileges on db_school.* to 'myroot'@'123.123.12.123' identified by 'mypass' with grant option;指定IP段用户赋权
mysql> grant all privileges on db_school.* to 'myroot'@'123.123.%' identified by 'mypass' with grant option;给用户myroot赋予数据库db_school中表stu1的查询和新增的权限
mysql> grant select,update on db_school.stu1 to 'myroot'@'123.123.12.123' identified by 'mypass' with grant option;解除权限：
mysql> revoke select on db_school.stu1 from 'myroot'@'123.123.12.123' with grant option; mysql> show grants for 'myroot'@'123.123.12.123'; +----------------------------------------------------------------------------------+ | Grants for 'myroot'@'123.123.12.123' | +----------------------------------------------------------------------------------+ | GRANT USAGE ON *.* TO 'myroot'@'123.123.12.123' | | GRANT UPDATE ON 'db_school'.'stu1' TO 'myroot'@'123.123.12.123' WITH GRANT OPTION| +----------------------------------------------------------------------------------+删除用户
mysql> drop user 'myroot'@'123.123.12.123';修改密码
mysqld_safe --user=mysql --skip-grant-tables --skip-networking & mysql use mysql; update user set authentication_string=password('root123') where user='root'; flush privileges; exit; service mysqld restart;