ALTER USER
ALTER USER 语句用于更改 TiDB 权限系统内的已有用户。和 MySQL 一样，在 TiDB 权限系统中，用户是用户名和用户名所连接主机的组合。因此，可创建一个用户 'newuser2'@'192.168.1.1'，使其只能通过 IP 地址 192.168.1.1 进行连接。相同的用户名从不同主机登录时可能会拥有不同的权限。
语法图
- AlterUserStmt
- UserSpecList
- UserSpec
- Username
- AuthOption
AlterUserStmt ::=
'ALTER' 'USER' IfExists (UserSpecList RequireClauseOpt ConnectionOptions PasswordOrLockOptions | 'USER' '(' ')' 'IDENTIFIED' 'BY' AuthString)
UserSpecList ::=
UserSpec ( ',' UserSpec )*
UserSpec ::=
Username AuthOption
Username ::=
StringName ('@' StringName | singleAtIdentifier)? | 'CURRENT_USER' OptionalBraces
AuthOption ::=
( 'IDENTIFIED' ( 'BY' ( AuthString | 'PASSWORD' HashString ) | 'WITH' StringName ( 'BY' AuthString | 'AS' HashString )? ) )?
示例
CREATE USER 'newuser' IDENTIFIED BY 'newuserpassword';
Query OK, 1 row affected (0.01 sec)
SHOW CREATE USER 'newuser';
+----------------------------------------------------------------------------------------------------------------------------------------------------------------------+
| CREATE USER for newuser@% |
+----------------------------------------------------------------------------------------------------------------------------------------------------------------------+
| CREATE USER 'newuser'@'%' IDENTIFIED WITH 'mysql_native_password' AS '*5806E04BBEE79E1899964C6A04D68BCA69B1A879' REQUIRE NONE PASSWORD EXPIRE DEFAULT ACCOUNT UNLOCK |
+----------------------------------------------------------------------------------------------------------------------------------------------------------------------+
1 row in set (0.00 sec)
ALTER USER 'newuser' IDENTIFIED BY 'newnewpassword';
Query OK, 0 rows affected (0.02 sec)
SHOW CREATE USER 'newuser';
+----------------------------------------------------------------------------------------------------------------------------------------------------------------------+
| CREATE USER for newuser@% |
+----------------------------------------------------------------------------------------------------------------------------------------------------------------------+
| CREATE USER 'newuser'@'%' IDENTIFIED WITH 'mysql_native_password' AS '*FB8A1EA1353E8775CA836233E367FBDFCB37BE73' REQUIRE NONE PASSWORD EXPIRE DEFAULT ACCOUNT UNLOCK |
+----------------------------------------------------------------------------------------------------------------------------------------------------------------------+
1 row in set (0.00 sec)
MySQL 兼容性
- 在 MySQL 中，
ALTER语句用于更改属性，例如使密码失效。但 TiDB 尚不支持此功能。