185. Department Top Three Salaries

Question

The Employee table holds all employees. Every employee has an Id, and there is also a column for the 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            |
+----+-------+--------+--------------+

The Department table holds all departments of the company.

+----+----------+
| Id | Name     |
+----+----------+
| 1  | IT       |
| 2  | Sales    |
+----+----------+

Write a SQL query to find employees who earn the top three salaries in each of the department. For the above tables, your SQL query should return the following rows.

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

二刷

1. 这道题和上一题比起来，需要选出当前部门中前几高的工资，所以我们使用了count函数，来选出当前部门中，大于该员工工资个数不大于3的所有员工。

   # Write your MySQL query statement below
   SELECT d.Name as Department,
   e.Name as Employee,
   e.Salary as Salary
   FROM Department d, Employee e
   WHERE(
    SELECT COUNT(distinct Salary)
    FROM Employee
    WHERE Salary > e.Salary AND DepartmentId = d.Id
   ) < 3 AND e.DepartmentId = d.Id
   ORDER BY d.Id, e.Salary desc;
   

引用

1.[LeetCode] Department Top Three Salaries 系里前三高薪水](https://www.cnblogs.com/grandyang/p/5367670.html)