우유와 요거트가 담긴 장바구니 - Summer/Winter Coding(2019) - GROUP BY, JOIN

 

문제

programmers.co.kr/learn/courses/30/lessons/62284

코딩테스트 연습 - 우유와 요거트가 담긴 장바구니

 

 

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1. 우유 구매자 목록 총 8명
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SELECT CART_ID FROM CART_PRODUCTS 
    WHERE NAME = 'Milk' 
        GROUP BY CART_ID 
        ORDER BY CART_ID ASC
------------------------------------------
cart_id
286
287
448
578
636
977
996
1048
------------------------------------------
2. 요거트 구매자 목록 총 8명
------------------------------------------
SELECT CART_ID FROM CART_PRODUCTS 
    WHERE NAME = 'Yogurt' 
        GROUP BY CART_ID 
        ORDER BY CART_ID ASC
------------------------------------------
cart_id
286
448
578
789
830
977
1034
1048
 
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3. 우유, 요거트 동시 구매자 목록 총 5명
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SELECT A.CART_ID AS CART_ID FROM
 
        (SELECT CART_ID FROM CART_PRODUCTS 
            WHERE NAME = 'Milk' 
                GROUP BY CART_ID 
                ORDER BY CART_ID ASC) A,
 
        (SELECT CART_ID FROM CART_PRODUCTS
            WHERE NAME = 'Yogurt' 
                GROUP BY CART_ID 
                ORDER BY CART_ID ASC) B
 
    WHERE A.CART_ID = B.CART_ID
------------------------------------------
cart_id
286
448
578
977
1048