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

Create table If Not Exists Employee (Id int, Name varchar(255), Salary int, DepartmentId int)

Create table If Not Exists Department (Id int, Name varchar(255))

Truncate table Employee

insert into Employee (Id, Name, Salary, DepartmentId) values ('1', 'Joe', '70000', '1')

insert into Employee (Id, Name, Salary, DepartmentId) values ('2', 'Henry', '80000', '2')

insert into Employee (Id, Name, Salary, DepartmentId) values ('3', 'Sam', '60000', '2')

insert into Employee (Id, Name, Salary, DepartmentId) values ('4', 'Max', '90000', '1')

Truncate table Department

insert into Department (Id, Name) values ('1', 'IT')

insert into Department (Id, Name) values ('2', 'Sales')

 

---

 

select d.Name Department, e1.Name Employee, e1.Salary
from Employee e1 
join Department d
on e1.DepartmentId = d.Id
where 3 > (select count(distinct(e2.Salary)) 
                  from Employee e2 
                  where e2.Salary > e1.Salary 
                  and e1.DepartmentId = e2.DepartmentId
                  );