SQL之DCL(管理用户.权限)

SQL之DCL(管理用户.权限)

管理用户：

1.添加用户
2.删除用户
3.修改密码
  (修改root密码、修改普通用户密码)
4.查询用户

1.添加用户

CREATE USER '用户名'@'主机名' IDENTIFIED BY '密码';
-- localhost:当前主机 、% 任意主机
举例：
	CREATE USER 'xiaohong'@'localhost' IDENTIFIED BY '123';
	CREATE USER 'xiaoli'@'%' IDENTIFIED BY '123';

2.删除用户

drop user '用户名'@'主机名';
举例：
	DROP USER 'xiaoli'@'%';

3.修改密码

1.修改普通用户密码：
	
5.0:
	update user set password = password('新密码') where user = '用户名'；
	set password for '用户名'@'主机名' = password('新密码');	
	
	UPDATE USER SET PASSWORD = PASSWORD("456") WHERE USER = 'zhangsan';
	set password for 'zhangsan'@'localhost' = password('456');

8.0:
	ALTER USER '用户名'@'主机名' IDENTIFIED WITH mysql_native_password BY '新密码';
	
	ALTER USER 'zhangsan'@'localhost' IDENTIFIED WITH mysql_native_password BY '456';

2.修改root用户密码：
	已知原密码：
		
		ALTER USER 'root'@'localhost' IDENTIFIED WITH mysql_native_password BY '123456';
		
	忘记原密码：