SQL 잘하시는분? 질문 있씁니다


SELECT A.PRODUCT_CODE, SUM(A.PRICE * B.SALES_AMOUNT)  AS SALES

FROM PRODUCT AS A INNER JOIN OFFLINE_SALE AS B ON A.PRODUCT_ID = B.PRODUCT_ID

GROUP BY PRODUCT_CODE

ORDER BY SALES DESC, PRODUCT_CODE



여기서 SUM 알 안쓰면 정답이 아닌거 같은데 정확히 어떤 기준으로 나오는지 모르겠습니다.


https://school.programmers.co.kr/learn/courses/30/lessons/131533