GRANT <role>
GRANT <role> 语句用于将之前创建的角色授予给现有用户。用户可以通过 SET ROLE <rolename> 语句拥有角色权限，或者通过 SET ROLE ALL 语句拥有被授予的所有角色。
语法图
GrantRoleStmt:
RolenameList:
UsernameList:
示例
创建新角色 analyticsteam 和新用户 jennifer：
$ mysql -uroot
CREATE ROLE analyticsteam;
Query OK, 0 rows affected (0.02 sec)
GRANT SELECT ON test.* TO analyticsteam;
Query OK, 0 rows affected (0.02 sec)
CREATE USER jennifer;
Query OK, 0 rows affected (0.01 sec)
GRANT analyticsteam TO jennifer;
Query OK, 0 rows affected (0.01 sec)
需要注意的是，默认情况下，用户 jennifer 需要执行 SET ROLE analyticsteam 语句才能使用与角色相关联的权限：
$ mysql -ujennifer
SHOW GRANTS;
+---------------------------------------------+
| Grants for User |
+---------------------------------------------+
| GRANT USAGE ON *.* TO 'jennifer'@'%' |
| GRANT 'analyticsteam'@'%' TO 'jennifer'@'%' |
+---------------------------------------------+
2 rows in set (0.00 sec)
SHOW TABLES in test;
ERROR 1044 (42000): Access denied for user 'jennifer'@'%' to database 'test'
SET ROLE analyticsteam;
Query OK, 0 rows affected (0.00 sec)
SHOW GRANTS;
+---------------------------------------------+
| Grants for User |
+---------------------------------------------+
| GRANT USAGE ON *.* TO 'jennifer'@'%' |
| GRANT Select ON test.* TO 'jennifer'@'%' |
| GRANT 'analyticsteam'@'%' TO 'jennifer'@'%' |
+---------------------------------------------+
3 rows in set (0.00 sec)
SHOW TABLES IN test;
+----------------+
| Tables_in_test |
+----------------+
| t1 |
+----------------+
1 row in set (0.00 sec)
执行 SET DEFAULT ROLE 语句将用户 jennifer 与某一角色相关联，这样该用户无需执行 SET ROLE 语句就能拥有与角色相关联的权限。
$ mysql -uroot
SET DEFAULT ROLE analyticsteam TO jennifer;
Query OK, 0 rows affected (0.02 sec)
$ mysql -ujennifer
SHOW GRANTS;
+---------------------------------------------+
| Grants for User |
+---------------------------------------------+
| GRANT USAGE ON *.* TO 'jennifer'@'%' |
| GRANT Select ON test.* TO 'jennifer'@'%' |
| GRANT 'analyticsteam'@'%' TO 'jennifer'@'%' |
+---------------------------------------------+
3 rows in set (0.00 sec)
SHOW TABLES IN test;
+----------------+
| Tables_in_test |
+----------------+
| t1 |
+----------------+
1 row in set (0.00 sec)
MySQL 兼容性
GRANT <role> 语句与 MySQL 8.0 的角色功能完全兼容。如发现任何兼容性差异，请在 GitHub 上提交 issue。