角色 ( Role ) 可以用来批量管理用户，同一个角色下的用户，拥有相同的权限。那 MySQL 数据库是否也有这样的功能呢 ？

　　答案是肯定的。MySQL 5.7.X 可以通过 mysqlxies_priv 来模拟角色 (Role) 的功能。下面让我们来实验一下（测试的版本 MySQL 5.7.28）：

　　1 配置 proxy

　　mysql> show variables like "%proxy%"; #查看当前proxy是否开启，OFF 表示没有开启

　　+-----------------------------------+-------+

　　| Variable_name | Value |

　　+-----------------------------------+-------+

　　| check_proxy_users | OFF |

　　| mysql_native_password_proxy_users | OFF |

　　| proxy_user | |

　　| sha256_password_proxy_users | OFF |

　　+-----------------------------------+-------+

　　4 rows in set (0.02 sec)

　　mysql> set global check_proxy_users=on;

　　Query OK, 0 rows affected (0.00 sec)

　　mysql> set global mysql_native_password_proxy_users=on;

　　Query OK, 0 rows affected (0.01 sec)

　　mysql> exit2 创建角色和用户

　　mysql> create user role_dba;Query OK, 0 rows affected (1.03 sec)

　　mysql> create user 'jack';Query OK, 0 rows affected (0.01 sec)

　　mysql> create user 'mary';Query OK, 0 rows affected (0.01 sec)

　　用户为设置密码，如需密码可以使用 identified by '####' 设置；

　　3 权限映射将 role_dba 的权限映射（ map ）到 jack 、mary

　　mysql> grant proxy on role_dba to jack;Query OK, 0 rows affected (0.02 sec)

　　mysql> grant proxy on role_dba to mary;Query OK, 0 rows affected (0.01 sec)4 给用户赋权给 role_dba 赋权（模拟 role 赋权）

　　mysql> grant select on *.* to role_dba;

　　Query OK, 0 rows affected (0.01 sec)

　　mysql> show grants for role_dba;

　　+---------------------------------------+

　　| Grants for role_dba@% |

　　+---------------------------------------+

　　| GRANT SELECT ON *.* TO 'role_dba'@'%' |

　　+---------------------------------------+

　　1 row in set (0.00 sec)

　　mysql> show grants for jack;

　　+---------------------------------------------+

　　| Grants for jack@% |

　　+---------------------------------------------+

　　| GRANT USAGE ON *.* TO 'jack'@'%' |

　　| GRANT PROXY ON 'role_dba'@'%' TO 'jack'@'%' |

　　+---------------------------------------------+

　　2 rows in set (0.00 sec)

　　mysql> show grants for mary;

　　+---------------------------------------------+

　　| Grants for mary@% |

　　+---------------------------------------------+

　　| GRANT USAGE ON *.* TO 'mary'@'%' |

　　| GRANT PROXY ON 'role_dba'@'%' TO 'mary'@'%' |

　　+---------------------------------------------+

　　2 rows in set (0.00 sec)

　　5 查看 mysqlxies_priv

　　mysql> select * from mysqlxies_priv;

　　+-----------+------+--------------+--------------+------------+----------------------+---------------------+

　　| Host | User | Proxied_host | Proxied_user | With_grant | Grantor | Timestamp |

　　+-----------+------+--------------+--------------+------------+----------------------+---------------------+

　　| localhost | root | | | 1 | boot@connecting host | 0000-00-00 00:00:00 |

　　| % | will | % | will_dba | 0 | root@localhost | 0000-00-00 00:00:00 |

　　| % | tom | % | will_dba | 0 | root@localhost | 0000-00-00 00:00:00 |

　　| % | jack | % | role_dba | 0 | root@localhost | 0000-00-00 00:00:00 |

　　| % | mary | % | role_dba | 0 | root@localhost | 0000-00-00 00:00:00 |

　　+-----------+------+--------------+--------------+------------+----------------------+---------------------+

　　5 rows in set (0.01 sec)6 验证

　　$ mysql -h 127.0.0.1 -u jack

　　Welcome to the MySQL monitor. Commands end with ; or \g.

　　Your MySQL connection id is 249

　　Server version: 5.7.28-log MySQL Community Server (GPL)

　　Copyright (c) 2000, 2021, Oracle and/or its affiliates. All rights reserved.

　　Oracle is a registered trademark of Oracle Corporation and/or its

　　affiliates. Other names may be trademarks of their respective

　　owners.

　　Type 'help;' or '\h' for help. Type '\c' to clear the current input statement.

　　mysql> select * from test.ssd limit 1;

　　+---+------+------+

　　| a | b | c |

　　+---+------+------+

　　| 1 | NULL | NULL |

　　+---+------+------+

　　1 row in set (0.01 sec)

　　mysqlxies_priv 仅仅是对 Role 的模拟，和 Oracle 的角色还是有所不同的；官方称呼为 Role like。