[SQL문제풀기] 주문량이 많은 아이스크림들 조회하기

문제

MYSQL

내가 작성한 오답

SELECT H.FLAVOR
FROM FIRST_HALF H
JOIN JULY J ON H.FLAVOR = J.FLAVOR
GROUP BY H.FLAVOR 
ORDER BY H.TOTAL_ORDER+J.TOTAL_ORDER DESC
LIMIT 3;

내가 작성한 정답

SELECT H.FLAVOR
FROM FIRST_HALF H
JOIN JULY J ON H.FLAVOR = J.FLAVOR
GROUP BY H.FLAVOR 
ORDER BY sum(H.TOTAL_ORDER)+sum(J.TOTAL_ORDER) DESC
LIMIT 3;

내가 이전에 작성한 정답

SELECT FLAVOR
FROM (SELECT F.FLAVOR , F.TOTAL_ORDER+SUM(J.TOTAL_ORDER) TOTAL
        FROM FIRST_HALF F
        JOIN JULY J ON F.FLAVOR = J.FLAVOR
        GROUP BY J.FLAVOR, F.TOTAL_ORDER
        ORDER BY TOTAL DESC
        LIMIT 3) TB

ORACLE

내가 작성한 정답

--1
SELECT J.FLAVOR
FROM FIRST_HALF H
JOIN JULY J ON H.FLAVOR = J.FLAVOR
GROUP BY J.FLAVOR
ORDER BY SUM(H.TOTAL_ORDER)+SUM(J.TOTAL_ORDER) DESC
FETCH FIRST 3 ROWS ONLY;

--2
SELECT FLAVOR
FROM (SELECT H.FLAVOR, SUM(J.TOTAL_ORDER)+SUM(H.TOTAL_ORDER) O
      FROM FIRST_HALF H
      JOIN JULY J ON H.FLAVOR=J.FLAVOR
      GROUP BY H.FLAVOR
      ORDER BY O DESC) OO
WHERE ROWNUM <=3;