184 Department Highest Salary

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

The Department table holds all departments of the company.

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

SELECT D.Name AS Department ,E.Name AS Employee ,E.Salary 
FROM
    Employee E,
    (SELECT DepartmentId,max(Salary) as max FROM Employee GROUP BY DepartmentId) T,
    Department D
WHERE E.DepartmentId = T.DepartmentId 
  AND E.Salary = T.max
  AND E.DepartmentId = D.id

SELECT D.Name,A.Name,A.Salary 
FROM 
    Employee A,
    Department D   
WHERE A.DepartmentId = D.Id 
  AND NOT EXISTS 
  (SELECT 1 FROM Employee B WHERE B.Salary > A.Salary AND A.DepartmentId = B.DepartmentId) 

SELECT D.Name AS Department ,E.Name AS Employee ,E.Salary 
from 
    Employee E,
    Department D 
WHERE E.DepartmentId = D.id 
  AND (DepartmentId,Salary) in 
  (SELECT DepartmentId,max(Salary) as max FROM Employee GROUP BY DepartmentId)