SQL/GROUP BY
[프로그래머스 ORACLE SQL]카테고리 별 도서 판매량 집계하기★LEFT , RIGHT , FULL OUTER JOIN★FROM 서브쿼리
goAhEAd_29
2023. 6. 21. 22:32
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https://school.programmers.co.kr/learn/courses/30/lessons/144855?language=oracle
SELECT CATEGORY, SUM(SALES) AS TOTAL_SALES FROM
(SELECT A.BOOK_ID AS BOOK_ID , A.CATEGORY AS CATEGORY, B.SALES_DATE AS SALES_DATE, B.SALES AS SALES FROM BOOK A RIGHT JOIN BOOK_SALES B
ON A.BOOK_ID = B.BOOK_ID
WHERE TO_CHAR(SALES_DATE , 'YYYY-MM') = '2022-01')
GROUP BY CATEGORY
ORDER BY CATEGORY
==> LEFT , FULL OUTER , RIGHT JOIN 모두 가능하다!
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