[프로그래머스 ORACLE SQL]5월 식품들의 총매출 조회하기★INNER JOIN

5월 식품들의 총매출 조회하기1

5월 식품들의 총매출 조회하기2

https://school.programmers.co.kr/learn/courses/30/lessons/131117

프로그래머스

SELECT A.PRODUCT_ID, B.PRODUCT_NAME , SUM(A.AMOUNT * B.PRICE) AS TOTAL_SALES FROM (
(SELECT PRODUCT_ID , PRODUCE_DATE ,SUM(AMOUNT) AS AMOUNT 
    FROM FOOD_ORDER
        GROUP BY PRODUCT_ID , PRODUCE_DATE HAVING TO_CHAR(PRODUCE_DATE, 'YYYY-MM') = '2022-05' ORDER BY PRODUCT_ID) A INNER JOIN FOOD_PRODUCT B
        ON A.PRODUCT_ID = B.PRODUCT_ID)
GROUP BY A.PRODUCT_ID , B.PRODUCT_NAME
ORDER BY TOTAL_SALES DESC , A.PRODUCT_ID ASC

==> FOOD_PRODUCT 에 다있는게 아니더라!!! ==> INNER JOIN을 통해 교집합 생성하는것이 좋다!!!