leetcode-database-185. Department Top Three Salaries

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  |
+------------+----------+--------+

题意:部门前3高的工资倒序排名

这道题是抄袭的最简练的答案，最近脑袋秀逗了，弄明白了又不明白了，不明白好不容易明白了改天看又懵了。

思路:

select count(distinct(salary)) from Employee

where departmentid=e.departmentid

and salary>e.salary

挑选出比e.salary工资高的salary个数小于3，保证e.salary的工资能够排名在前三。

最终sql：

select d.name Department,e.Name Employee,e.Salary Salary

from Employee e,Department d

where (select count(distinct(salary)) from Employee

where departmentid=e.departmentid

and salary>e.salary)<3

and e.departmentid=d.id

order by e.departmentid,e.salary desc;