[SQL문제풀기] 즐겨찾기가 가장 많은 식당 정보 출력하기

문제

MYSQL, ORACLE

내가 작성한 오답

SELECT FOOD_TYPE, REST_ID, REST_NAME, FAVORITES
FROM REST_INFO
WHERE REST_ID IN
(SELECT REST_ID FROM REST_INFO GROUP BY FOOD_TYPE HAVING MAX(FAVORITES))
ORDER BY FOOD_TYPE DESC

내가 작성한 정답

SELECT FOOD_TYPE, REST_ID, REST_NAME, FAVORITES
FROM REST_INFO
WHERE (FOOD_TYPE, FAVORITES) IN (
    SELECT FOOD_TYPE, MAX(FAVORITES) FROM REST_INFO GROUP BY FOOD_TYPE )
ORDER BY FOOD_TYPE DESC

다른 사람이 작성한 정답

SELECT FOOD_TYPE,
       REST_ID,
       REST_NAME,
       FAVORITES
FROM 
(
SELECT FOOD_TYPE,
       REST_ID,
       REST_NAME,
       SUM(FAVORITES) AS FAVORITES,
       RANK() OVER(PARTITION BY FOOD_TYPE ORDER BY SUM(FAVORITES) DESC) AS FAVORITES_RANK
FROM REST_INFO
GROUP BY FOOD_TYPE, REST_NAME
) a
WHERE FAVORITES_RANK = 1
ORDER BY FOOD_TYPE DESC