저자 별 카테고리 별 매출액 집계하기

SELECT A.AUTHOR_ID,
B.AUTHOR_NAME,
A.CATEGORY,
SUM(C.SALES * A.PRICE) AS TOTAL_SALES 
FROM BOOK A JOIN AUTHOR B
ON A.AUTHOR_ID = B.AUTHOR_ID
JOIN BOOK_SALES C
ON A.BOOK_ID = C.BOOK_ID
WHERE C.SALES_DATE LIKE '2022-01%'
GROUP BY A.AUTHOR_ID, A.CATEGORY
ORDER BY A.AUTHOR_ID, A.CATEGORY DESC;