카테고리 별 도서 판매량 집계하기

게시 2024/01/20

By tonyleekorea 1 분읽는 시간

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

문제 풀이

  
SELECT
    B.CATEGORY,
    SUM(S.SALES) AS "TOTAL_SALES"
FROM
    BOOK_SALES S, BOOK B
WHERE
    B.BOOK_ID = S.BOOK_ID
    AND SALES_DATE BETWEEN TO_DATE(20220101, 'YYYY-MM-DD') AND TO_DATE(20220131, 'YYYY-MM-DD')
GROUP BY
    B.CATEGORY
ORDER BY
    B.CATEGORY;

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

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