[MySQL] 프로그래머스 - 자동차 평균 대여 기간 구하기

https://school.programmers.co.kr/learn/courses/30/lessons/157342

프로그래머스

 

 

문제

CAR_RENTAL_COMPANY_RENTAL_HISTORY 테이블에서 평균 대여 기간이 7일 이상인 자동차들의 자동차 ID와 평균 대여 기간(컬럼명: AVERAGE_DURATION) 리스트를 출력하는 SQL문을 작성해주세요. 평균 대여 기간은 소수점 두번째 자리에서 반올림하고, 결과는 평균 대여 기간을 기준으로 내림차순 정렬해주시고, 평균 대여 기간이 같으면 자동차 ID를 기준으로 내림차순 정렬해주세요.

 

정답

 

SELECT CAR_ID, ROUND(AVG(DATEDIFF(END_DATE, START_DATE)+1), 1) AS AVERAGE_DURATION 
FROM CAR_RENTAL_COMPANY_RENTAL_HISTORY
GROUP BY CAR_ID
HAVING AVERAGE_DURATION >= 7
ORDER BY AVERAGE_DURATION DESC, CAR_ID DESC;