MySQL对DROP USER似乎有效，但该用户仍存在于MySQL.users表中？
首先借助select语句从MySQL.user表中检查所有用户和主机，如下所示
mysql> select user,host from MySQL.user;
以下是输出
+------------------+-----------+ | user | host | +------------------+-----------+ | Bob | % | | Manish | % | | User2 | % | | mysql.infoschema | % | | mysql.session | % | | mysql.sys | % | | root | % | | @UserName@ | localhost | | Adam Smith | localhost | | James | localhost | | John | localhost | | John Doe | localhost | | User1 | localhost | | am | localhost | | hbstudent | localhost | | mysql.infoschema | localhost | | mysql.session | localhost | +------------------+-----------+ 17 rows in set (0.00 sec)
现在，从MySQL.user表中删除用户“hbstudent”。查询如下-
mysql> drop user 'hbstudent'@'localhost';
现在检查MySQL.user表以确认该用户是否仍然存在于MySQL.user表中。查询如下-
mysql> select user,host from MySQL.user;
以下是输出
+------------------+-----------+ | user | host | +------------------+-----------+ | Bob | % | | Manish | % | | User2 | % | | mysql.infoschema | % | | mysql.session | % | | mysql.sys | % | | root | % | | @UserName@ | localhost | | Adam Smith | localhost | | James | localhost | | John | localhost | | John Doe | localhost | | User1 | localhost | | am | localhost | | mysql.infoschema | localhost | | mysql.session | localhost | +------------------+-----------+ 16 rows in set (0.00 sec)