131534.md

프로그래머스 131534

'상품을 구매한 회원 비율 구하기'

🔗 https://school.programmers.co.kr/learn/courses/30/lessons/131534

SELECT YEAR, MONTH, COUNT(DISTINCT O.USER_ID) AS PURCHASED_USERS
        , ROUND(COUNT(DISTINCT O.USER_ID)/CUNT_TOT,1) AS PUCHASED_RATIO
FROM (SELECT *, COUNT(USER_ID) OVER() AS CUNT_TOT FROM USER_INFO 
        WHERE YEAR(JOINED)='2021') AS U
INNER JOIN (SELECT *, YEAR(SALES_DATE) AS YEAR, MONTH(SALES_DATE) AS MONTH
            FROM ONLINE_SALE) AS O
    ON O.USER_ID=U.USER_ID
GROUP BY 1,2
ORDER BY 1,2