一道腾讯笔试题，求教

Question

Employee 表包含所有员工信息，每个员工有其对应的工号 Id，姓名 Name，工资 Salary 和部门编号 DepartmentId 。

+----+-------+--------+--------------+
| Id | Name  | Salary | DepartmentId |
+----+-------+--------+--------------+
| 1  | Joe   | 85000  | 1            |
| 2  | Henry | 80000  | 2            |
| 3  | Sam   | 60000  | 2            |
| 4  | Max   | 90000  | 1            |
| 5  | Janet | 69000  | 1            |
| 6  | Randy | 85000  | 1            |
| 7  | Will  | 70000  | 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，找出每个部门获得前三高工资的所有员工。例如，根据上述给定的表，查询结果应返回：

+------------+----------+--------+
| Department | Employee | Salary |
+------------+----------+--------+
| IT         | Max      | 90000  |
| IT         | Randy    | 85000  |
| IT         | Joe      | 85000  |
| Sales      | Will     | 70000  |
| Sales      | Henry    | 80000  |
| Sales      | Sam      | 60000  |
+------------+----------+--------+

select 
department, name as employee, salary
from 
(select d.name as Department , e.name as Name, e.salary 
rank() over(partition by e.id order by salary desc) as s_rank
from employee e, department d 
where e.departmentId  = d.id ) t1
where s_rank <= 3

Answer 1

select B.Name as Department, A.Name as Employee, A.Salary 
from Employee A, Department B where A.DepartmentId=B.Id and (
    # 如果当前记录在部门中排名进入前三
    select count(1) from Employee C 
    where C.DepartmentId=A.DepartmentId and C.Salary >= A.Salary
) <= 3 
order by A.DepartmentId ASC, A.Salary DESC