[프로그래머스] 카테고리 별 도서 판매량 집계하기 SELECT T1.CATEGORY, SUM(T2.SALES) AS TOTAL_SALES FROM BOOK T1, BOOK_SALES T2 WHERE T1.BOOK_ID = T2.BOOK_ID AND T2.SALES_DATE LIKE '2022-01%' GROUP BY T1.CATEGORY ORDER BY T1.CATEGORY SQL 2023.07.13
