[Programmers] 016 - 상품별 오프라인 매출 구하기

SELECT P.PRODUCT_CODE
     , (P.PRICE * SUM(S.SALES_AMOUNT)) SALES
  FROM PRODUCT P
 INNER JOIN OFFLINE_SALE S ON P.PRODUCT_ID = S.PRODUCT_ID
 GROUP BY P.PRODUCT_ID
 ORDER BY SALES DESC, P.PRODUCT_CODE ASC