DROP USER

DROP USER 'idontexist';

ERROR 1396 (HY000): Operation DROP USER failed for idontexist@%

DROP USER IF EXISTS 'idontexist';

Query OK, 0 rows affected (0.01 sec)

CREATE USER 'newuser' IDENTIFIED BY 'mypassword';

GRANT ALL ON test.* TO 'newuser';

+-------------------------------------------------+
| Grants for newuser@%                            |
+-------------------------------------------------+
| GRANT USAGE ON *.* TO 'newuser'@'%'             |
| GRANT ALL PRIVILEGES ON test.* TO 'newuser'@'%' |
+-------------------------------------------------+
2 rows in set (0.00 sec)

REVOKE ALL ON test.* FROM 'newuser';

+-------------------------------------+
| Grants for newuser@%                |
| GRANT USAGE ON *.* TO 'newuser'@'%' |
+-------------------------------------+
1 row in set (0.00 sec)

DROP USER 'newuser';

Query OK, 0 rows affected (0.14 sec)

SHOW GRANTS FOR 'newuser';

在 TiDB 中删除不存在的用户时，使用可避免出现警告。。

CREATE USER
SHOW CREATE USER