LeetCode in Kotlin
184. Department Highest Salary
Medium
SQL Schema
Table: Employee
+--------------+---------+
| Column Name | Type |
+--------------+---------+
| id | int |
| name | varchar |
| salary | int |
| departmentId | int |
+--------------+---------+
id is the primary key column for this table.
departmentId is a foreign key of the ID from the `Department` table.
Each row of this table indicates the ID, name, and salary of an employee. It also contains the ID of their department.
Table: Department
+-------------+---------+
| Column Name | Type |
+-------------+---------+
| id | int |
| name | varchar |
+-------------+---------+
id is the primary key column for this table.
Each row of this table indicates the ID of a department and its name.
Write an SQL query to find employees who have the highest salary in each of the departments.
Return the result table in any order.
The query result format is in the following example.
Example 1:
Input:
Employee table:
+----+-------+--------+--------------+
| id | name | salary | departmentId |
+----+-------+--------+--------------+
| 1 | Joe | 70000 | 1 |
| 2 | Jim | 90000 | 1 |
| 3 | Henry | 80000 | 2 |
| 4 | Sam | 60000 | 2 |
| 5 | Max | 90000 | 1 |
+----+-------+--------+--------------+
Department table:
+----+-------+
| id | name |
+----+-------+
| 1 | IT |
| 2 | Sales |
+----+-------+
Output:
+------------+----------+--------+
| Department | Employee | Salary |
+------------+----------+--------+
| IT | Jim | 90000 |
| Sales | Henry | 80000 |
| IT | Max | 90000 |
+------------+----------+--------+
Explanation: Max and Jim both have the highest salary in the IT department and Henry has the highest salary in the Sales department.
Solution
# Write your MySQL query statement below
SELECT
d.Name AS Department,
Sel.Name AS Employee,
Sel.Salary AS Salary
FROM
(
SELECT
Name,
Salary,
DepartmentId,
DENSE_RANK() OVER (PARTITION BY DepartmentId ORDER BY Salary DESC) AS dr
FROM Employee
) AS Sel
INNER JOIN Department d ON d.Id = Sel.DepartmentId
WHERE Sel.dr = 1