Employee 表包含所有员工信息,每个员工有其对应的 Id, salary 和 department Id 。
+----+-------+--------+--------------+
| Id | Name | Salary | DepartmentId |
+----+-------+--------+--------------+
| 1 | Joe | 70000 | 1 |
| 2 | Henry | 80000 | 2 |
| 3 | Sam | 60000 | 2 |
| 4 | Max | 90000 | 1 |
| 5 | Janet | 69000 | 1 |
| 6 | Randy | 85000 | 1 |
+----+-------+--------+--------------+
Department 表包含公司所有部门的信息。
+----+----------+
| Id | Name |
+----+----------+
| 1 | IT |
| 2 | Sales |
+----+----------+
编写一个 SQL 查询,找出每个部门工资前三高的员工
Code
- (select count(distinct(salary)) from employee
where departmentid = e.departmentid and salary>e.salary)< 3- 嵌套员工表作为过滤表
- e表的工资限制 = 与过滤表的比较 + 过滤表工资数目的限制
select d.name department, e.name employee, e.salary
from employee e inner join department d on e.departmentid = d.id
where
(select count(distinct(salary)) from employee
where departmentid = e.departmentid and salary>e.salary)< 3
order by e.departmentid, e.salary desc