[프로그래머스_SQL] 카테고리 별 도서 판매량 집계하기

📜문제

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

📜정답

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    SELECT A.CATEGORY,SUM(B.SALES)AS TOTAL_SALES 
    FROM BOOK A INNER JOIN BOOK_SALES B
    ON A.BOOK_ID=B.BOOK_ID
    WHERE DATE_FORMAT(B.SALES_DATE,'%Y-%m')='2022-01'
    GROUP BY A.CATEGORY  
    ORDER BY A.CATEGORY ASC

📜노트

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• DATE_FORMAT(컬럼명,’원하는 날짜 형식’)