SQL | 걷기반 7. 랭크게임 하다가 싸워서 피드백 남겼어요...

아래와 같은 lol_feedbacks(LOL 피드백 테이블)이 있습니다.

25. lol_feedbacks 테이블에서 만족도 점수(satisfaction_score)에 따라 피드백을 내림차순으로 정렬하는 쿼리를 작성해주세요!

SELECT *
FROM lol_feedbacks
ORDER BY satisfaction_score DESC ;

26. lol_feedbacks 테이블에서 각 유저별로 최신 피드백을 찾는 쿼리를 작성해주세요!

SELECT user_name,
       MAX(feedback_date)
FROM lol_feedbacks
GROUP BY user_name ;

27.lol_feedbacks 테이블에서 만족도 점수가 5점인 피드백의 수를 계산하는 쿼리를 작성해주세요!

SELECT COUNT(1) cnt_feedback
FROM lol_feedbacks
WHERE satisfaction_score=5 ;

28. lol_feedbacks 테이블에서 가장 많은 피드백을 남긴 상위 3명의 고객을 찾는 쿼리를 작성해주세요!

SELECT RANK OVER(PARTITON BY user_name ORDER BY feedback_date DESC) feedback_rank
FROM lol_feedbacks
WHERE feedback_rank<=3 ;

29. lol_feedbacks 테이블에서 평균 만족도 점수가 가장 높은 날짜를 찾는 쿼리를 작성해주세요!

SELECT feedback_date
       AVG(satisfaction_score) avg_score
FROM lol_feedbacks
GROUP BY feedback_date
ORDER BY avg_score DESC
LIMIT 1 ;