DROP USER
DROP USER 语句用于从 TiDB 系统数据库中删除用户。如果用户不存在，使用关键词 IF EXISTS 可避免出现警告。
语法图
DropUserStmt:
Username:
示例
mysql> DROP USER idontexist;
ERROR 1396 (HY000): Operation DROP USER failed for idontexist@%
mysql> DROP USER IF EXISTS idontexist;
Query OK, 0 rows affected (0.01 sec)
mysql> CREATE USER newuser IDENTIFIED BY 'mypassword';
Query OK, 1 row affected (0.02 sec)
mysql> GRANT ALL ON test.* TO 'newuser';
Query OK, 0 rows affected (0.03 sec)
mysql> SHOW GRANTS FOR 'newuser';
+-------------------------------------------------+
| Grants for newuser@% |
+-------------------------------------------------+
| GRANT USAGE ON *.* TO 'newuser'@'%' |
| GRANT ALL PRIVILEGES ON test.* TO 'newuser'@'%' |
+-------------------------------------------------+
2 rows in set (0.00 sec)
mysql> REVOKE ALL ON test.* FROM 'newuser';
Query OK, 0 rows affected (0.03 sec)
mysql> SHOW GRANTS FOR 'newuser';
+-------------------------------------+
| Grants for newuser@% |
+-------------------------------------+
| GRANT USAGE ON *.* TO 'newuser'@'%' |
+-------------------------------------+
1 row in set (0.00 sec)
mysql> DROP USER newuser;
Query OK, 0 rows affected (0.14 sec)
mysql> SHOW GRANTS FOR newuser;
ERROR 1141 (42000): There is no such grant defined for user 'newuser' on host '%'
MySQL 兼容性
- 在 TiDB 中删除不存在的用户时，使用
IF EXISTS可避免出现警告。Issue #10196。