User Daily Active Engagement Counts in SQL

Question

From a `user_events` table, calculate how many distinct calendar days each `user_id` interacted with the application during the month of February 2026. Only include users with at least 3 active days.

Accepted Answer

Optimal Solution:
SELECT 
  user_id,
  COUNT(DISTINCT DATE(created_at)) AS active_days
FROM user_events
WHERE created_at >= '2026-02-01' 
  AND created_at < '2026-03-01'
GROUP BY user_id
HAVING COUNT(DISTINCT DATE(created_at)) >= 3
ORDER BY active_days DESC;

Technical Explanation:
Converts timestamp to date with `DATE(created_at)`, deduplicates daily actions with `COUNT(DISTINCT ...)`, and filters groups with `HAVING >= 3`.

event_id	user_id	created_at
1	101	2026-02-01 10:00:00
2	101	2026-02-01 15:00:00
3	101	2026-02-03 12:00:00
4	101	2026-02-05 09:00:00