1141. User Activity for the Past 30 Days I

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

Решение

SELECT
  activity_date AS day,
  COUNT(DISTINCT user_id) AS active_users
FROM Activity
WHERE activity_date BETWEEN DATE_SUB('2019-07-27', INTERVAL 29 DAY)
                         AND '2019-07-27'
GROUP BY activity_date;