출처

https://school.programmers.co.kr/learn/courses/30/lessons/144856

문제

풀이

SELECT
    A.AUTHOR_ID,
    AUTHOR_NAME,
    CATEGORY,
    SUM(SALES * PRICE) AS TOTAL_SALES
FROM BOOK B
    JOIN AUTHOR A ON B.AUTHOR_ID=A.AUTHOR_ID
    JOIN BOOK_SALES S ON B.BOOK_ID=S.BOOK_ID
WHERE
    SALES_DATE BETWEEN '2022-01-01' AND '2022-01-31'
GROUP BY
    A.AUTHOR_ID, CATEGORY
ORDER BY
    A.AUTHOR_ID, CATEGORY DESC