[LeetCode] 1141. User Activity for the Past 30 Days I

 

 

[문제]

이미지를 누르면 문제 링크로 넘어갑니다

 

 

[MySQL]

SELECT activity_date AS day
     , COUNT(DISTINCT user_id) AS active_users
FROM Activity
WHERE activity_date > DATE_SUB('2019-07-27', INTERVAL 30 DAY) 
  AND activity_date <= '2019-07-27'
GROUP BY activity_date