[Leetcode] Employees Earning More Than Their Managers (풀이)

Employees Earning More Than Their Managers 문제 바로가기 

Employees Earning More Than Their Managers - LeetCode

 

문제

Write an SQL query to find the employees who earn more than their managers.

Return the result table in any order.

The query result format is in the following example.

 

Example 1:

Input: 
Employee table:
+----+-------+--------+-----------+
| id | name  | salary | managerId |
+----+-------+--------+-----------+
| 1  | Joe   | 70000  | 3         |
| 2  | Henry | 80000  | 4         |
| 3  | Sam   | 60000  | Null      |
| 4  | Max   | 90000  | Null      |
+----+-------+--------+-----------+
Output: 
+----------+
| Employee |
+----------+
| Joe      |
+----------+
Explanation: Joe is the only employee who earns more than his manager.

---

풀이

-- employee 테이블에 managerID를 기준으로 SELF JOIN -> manager 테이블을 새로 만들기 

-- manager보다 salary가 employee 조건문 WHERE로 필터링

 

SELECT em.name AS Employee
FROM employee AS em
         INNER JOIN employee AS ma ON em.managerID = ma.id
WHERE em.salary > ma.salary

OUTPUT

{"headers": ["Employee"], "values": [["Joe"]]}