LeetCode - 1141. User Activity for the Past 30 Days I

 

해결일	언어	레벨	테스트명
20240814	SQL	easy	1141. User Activity for the Past 30 Days I

 

링크 : https://leetcode.com/problems/user-activity-for-the-past-30-days-i/

 

 

 

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내 코드

# Write your MySQL query statement below

SELECT
    activity_date day        
    ,COUNT(DISTINCT user_id) active_users 
FROM Activity 
WHERE activity_date BETWEEN DATE_SUB('2019-07-27', INTERVAL 30 DAY)+1 AND '2019-07-27'
GROUP BY activity_date

 

 

DATE_SUB 같은 시간 함수 관련해서 정리를 했다.

https://young-1-2.tistory.com/198

[SQL] 날짜 함수 정리

 

 

 

 

베스트 코드

SELECT activity_date as day, COUNT(DISTINCT user_id) as active_users
FROM Activity
WHERE datediff('2019-07-27',activity_date)<30 
AND activity_date <= '2019-07-27' 
GROUP BY activity_date