180607_Highest

The Employee table holds all employees. Every employee has an Id, a salary, 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

+----+-------+--------+--------------+

Id	Name	Salary	DepartmentId
1	Joe	70000	1
2	Henry	80000	2
3	Sam	60000	2
4	Max	90000	1

+----+-------+--------+--------------+
The Department table holds all departments of the company.

Id	Name
1	IT
2	Sales

+----+----------+

Id	Name
1	IT
2	Sales

+----+----------+
Write a SQL query to find employees who have the highest salary in each of the departments. For the above tables, Max has the highest salary in the IT department and Henry has the highest salary in the Sales department.

Department	Employee	Salary
IT	Max	90000
Sales	Henry	80000

+------------+----------+--------+

Department	Employee	Salary
IT	Max	90000
Sales	Henry	80000

+------------+----------+--------+

SELECT d.Name as Department, e.Name as Employee, e.Salary
FROM Employee as e, Department as d 
WHERE e.DepartmentId = d.Id
AND (e.DepartmentId, e.Salary) IN (SELECT DepartmentId, MAX(Salary) as max
             FROM Employee
             GROUP BY DepartmentId)