README.md

GROUP BY

프로그래머스 카테고리 별 도서 판매량 집계하기

SELECT CATEGORY, SUM(SALES) AS TOTAL_SALES
FROM BOOK_SALES JOIN BOOK
ON BOOK_SALES.BOOK_ID = BOOK.BOOK_ID
WHERE SALES_DATE BETWEEN '2022-01-01' AND '2022-01-31'
GROUP BY CATEGORY
ORDER BY CATEGORY ASC

저자 별 카테고리 별 매출액 집계하기

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