저자 별 카테고리 별 매출액 집계하기

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

• 문제 풀이

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

SELECT
    B.AUTHOR_ID,
    B.AUTHOR_NAME,
    A.CATEGORY,
    SUM(A.PRICE * C.SALES) AS "TOTAL_SALES"
FROM
    BOOK A, 
    AUTHOR B, 
    BOOK_SALES C
WHERE
    TO_CHAR(C.SALES_DATE, 'YYYYMM') = '202201'
    AND A.AUTHOR_ID = B.AUTHOR_ID
    AND A.BOOK_ID = C.BOOK_ID
GROUP BY
    B.AUTHOR_ID,
    B.AUTHOR_NAME,
    A.CATEGORY
ORDER BY
    B.AUTHOR_ID,
    A.CATEGORY DESC;

• 실행 결과