자동차 평균 대여 기간 구하기

• 문제
  
  
• 정답

SELECT CAR_ID, ROUND(AVG(DATEDIFF(END_DATE, START_DATE)+1), 1) 'AVERAGE_DURATION'
FROM CAR_RENTAL_COMPANY_RENTAL_HISTORY
GROUP BY 1
HAVING AVERAGE_DURATION > 6
ORDER BY 2 DESC, 1 DESC

• 결과