department-top-three-salaries

Description

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

Solution

select `d`.`Name` as `Department`, `e1`.`Name` as `Employee`, `e1`.`Salary` from `Employee` `e1`,
`Employee` `e2`, `Department` `d`
where `e1`.`DepartmentId` = `e2`.`DepartmentId`
and `e1`.`Salary` <= `e2`.`Salary`
and `d`.`Id` = `e1`.`DepartmentId`
group by `e1`.`Id`
having count(distinct `e2`.`Salary`) <= 3
order by `Department`, `Salary` desc;;

Note

If you have a better solution, you can star and fork Leetcode-database-problem then create a pull request.