184. Department Highest Salary

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Description

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  | Jim   | 90000  | 1            |

| 3  | Henry | 80000  | 2            |

| 4  | Sam   | 60000  | 2            |

| 5  | 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, your SQL query should return the following rows (order of rows does not matter).

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

| Department | Employee | Salary |

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

| IT         | Max      | 90000  |

| IT         | Jim      | 90000  |

| Sales      | Henry    | 80000  |

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

Explanation:

Max and Jim both have the highest salary in the IT department and Henry has the highest salary in the Sales department.

Solutions

SQL

SELECT
	Department.NAME AS Department,
	Employee.NAME AS Employee,
	Salary
FROM
	Employee,
	Department
WHERE
	Employee.DepartmentId = Department.Id
	AND ( Employee.DepartmentId, Salary )
    IN (SELECT DepartmentId, max( Salary )
        FROM Employee
        GROUP BY DepartmentId )