[프로그래머스SQL]카테고리 별 도서 판매량 집계하기

링크

SELECT B.CATEGORY, SUM(BS.SALES) 
AS TOTAL_SALES from BOOK_SALES AS BS
JOIN BOOK AS B
ON BS.BOOK_ID = B.BOOK_ID
WHERE YEAR(SALES_DATE) = '2022' 
	AND MONTH(SALES_DATE) = '01'
GROUP BY B.CATEGORY
ORDER BY B.CATEGORY;