sql外面再套一层吧，举例

create table employee( 
   dname varchar(20), -- 部门名 
   eid varchar(20), 
   ename varchar(20), 
   hiredate date, -- 入职日期 
   salary double -- 薪资
); 
insert into employee values('研发部','1001','刘备','2021-11-01',3000);
insert into employee values('研发部','1002','关羽','2021-11-02',5000);
insert into employee values('研发部','1003','张飞','2021-11-03',7000);
insert into employee values('研发部','1004','赵云','2021-11-04',7000);
insert into employee values('研发部','1005','马超','2021-11-05',4000);
insert into employee values('研发部','1006','黄忠','2021-11-06',4000);
insert into employee values('销售部','1007','曹操','2021-11-01',2000);
insert into employee values('销售部','1008','许褚','2021-11-02',3000);
insert into employee values('销售部','1009','典韦','2021-11-03',5000);
insert into employee values('销售部','1010','张辽','2021-11-04',6000);
insert into employee values('销售部','1011','徐晃','2021-11-05',9000);
insert into employee values('销售部','1012','曹洪','2021-11-06',6000);
全部分组排序
mysql> select  dname, ename, salary, row_number() over(partition by dname order by salary desc) as rn  from employee;+-----------+--------+--------+----+
| dname     | ename  | salary | rn |
+-----------+--------+--------+----+
| 研发部    | 张飞   |   7000 |  1 |
| 研发部    | 赵云   |   7000 |  2 |
| 研发部    | 关羽   |   5000 |  3 |
| 研发部    | 马超   |   4000 |  4 |
| 研发部    | 黄忠   |   4000 |  5 |
| 研发部    | 刘备   |   3000 |  6 |
| 销售部    | 徐晃   |   9000 |  1 |
| 销售部    | 张辽   |   6000 |  2 |
| 销售部    | 曹洪   |   6000 |  3 |
| 销售部    | 典韦   |   5000 |  4 |
| 销售部    | 许褚   |   3000 |  5 |
| 销售部    | 曹操   |   2000 |  6 |
+-----------+--------+--------+----+
12 rows in set (0.00 sec)
前三名
mysql> select * from ( select  dname, ename, salary, row_number() over(partition by dname order by salary desc ) as rn
 from employee ) a where rn<=3;
+-----------+--------+--------+----+
| dname     | ename  | salary | rn |
+-----------+--------+--------+----+
| 研发部    | 张飞   |   7000 |  1 |
| 研发部    | 赵云   |   7000 |  2 |
| 研发部    | 关羽   |   5000 |  3 |
| 销售部    | 徐晃   |   9000 |  1 |
| 销售部    | 张辽   |   6000 |  2 |
| 销售部    | 曹洪   |   6000 |  3 |
+-----------+--------+--------+----+
6 rows in set (0.00 sec)

学习了，赞！