mysql 用户授权：
1.创建用户：
create user 'user1'@'100.%' identified by 'pwd' //创建用户并无权限
2.授权：
grant all privileges on *.* TO 'user1'@'100.%' with grant option; //将所有权限授予user1
3.收回权限：
revoke all privileges on *.* From 'user1'@'100.%‘ with grant option; //将所有权限从user1收回