[프로그래머스 SQL] LV.3 대여 횟수가 많은 자동차들의 월별 대여 횟수 구하기

❓ Question

 

❗ Answer

SELECT MONTH(start_date) month, car_id, COUNT(car_id) RECORDS
    FROM car_rental_company_rental_history
    WHERE car_id IN (SELECT car_id
                        FROM car_rental_company_rental_history
                    WHERE start_date BETWEEN '2022-08-01' AND '2022-10-31'
                    GROUP BY car_id
                    HAVING COUNT(car_id) >= 5)
      AND start_date BETWEEN '2022-08-01' AND '2022-10-31'
    GROUP BY month, car_id
    HAVING RECORDS IS NOT NULL
    ORDER BY month, car_id DESC;

📌 Discussion

- sub-query inline view로 조건에 맞는 car_id만 불러와서 main-query에서 필터링

- HAVING 절에서도 연산자 사용가능