[SQL] 프로그래머스 : 카테고리 별 도서 판매량 집계하기

https://school.programmers.co.kr/learn/courses/30/lessons/144855

SELECT CATEGORY, SUM(SALES) AS TOTAL_SALES
FROM BOOK A
JOIN BOOK_SALES B 
ON A.BOOK_ID = B.BOOK_ID
WHERE SALES_DATE LIKE '2022-01-%'
GROUP BY CATEGORY
ORDER BY CATEGORY ASC;