[프로그래머스][SQL][ORACLE] lv 3 카테고리 별 도서 판매량

SELECT 
B.CATEGORY
, SUM(S.SALES) AS TOTAL_SALES
FROM 
BOOK B
INNER JOIN BOOK_SALES S
ON B.BOOK_ID = S.BOOK_ID
WHERE TO_CHAR(S.SALES_DATE, 'YYYY-MM' ) LIKE '2022-01'
GROUP BY B.CATEGORY
ORDER BY CATEGORY ASC

누워서 쓰니까 너무 힘들다