[프로그래머스-SQL 고득점 Kit] 상품을 구매한 회원 비율 구하기

Hi, There!
안녕하세요, 바오밥입니다.

 

 

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목차

• 문제
• 풀이

 

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문제

문제 내용

https://school.programmers.co.kr/learn/courses/30/lessons/131534?language=oracle

프로그래머스

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풀이

나의 풀이

- DBMS : Oracle 기준

SELECT 
    EXTRACT(YEAR FROM OS.SALES_DATE) YEAR,
    EXTRACT(MONTH FROM OS.SALES_DATE) MONTH,
    COUNT(DISTINCT(OS.USER_ID)) PUCHASED_USERS,
    ROUND(COUNT(DISTINCT(OS.USER_ID)) / (SELECT COUNT(*) 
                                         FROM USER_INFO 
                                         WHERE EXTRACT(YEAR FROM JOINED) = '2021'), 1) PUCHASED_RATIO

FROM 
    USER_INFO UI,
    ONLINE_SALE OS
    
WHERE
    UI.USER_ID = OS.USER_ID
    AND TO_CHAR(JOINED, 'YYYY') = '2021'

GROUP BY 
    EXTRACT(YEAR FROM OS.SALES_DATE),
    EXTRACT(MONTH FROM OS.SALES_DATE)
    
ORDER BY 1, 2