[SQL문제풀기] 카테고리 별 도서 판매량 집계하기

문제

MYSQL

내가 작성한 정답

SELECT CATEGORY, SUM(SALES) TOTAL_SALES
FROM BOOK B
JOIN BOOK_SALES S ON B.BOOK_ID = S.BOOK_ID AND DATE_FORMAT(S.SALES_DATE,'%y%m') ='2201'
GROUP BY CATEGORY
ORDER BY 1;

ORACLE

내가 작성한 정답

SELECT CATEGORY, SUM(SALES) TOTAL_SALES
FROM BOOK B
JOIN BOOK_SALES S ON B.BOOK_ID = S.BOOK_ID AND TO_CHAR(S.SALES_DATE,'YYMM') ='2201'
GROUP BY CATEGORY
ORDER BY 1;