SELECT DATE_ADD(LAST_DAY(o.order_date), INTERVAL 1 DAY) AS month_start, COUNT(o.order_id) AS order_count

FROM order_table o

GROUP BY 1

-- PostgreSQL / MySQL 8+ (через window functions)
WITH uniq_days AS (
  SELECT DISTINCT user_id, event_date
  FROM user_events
),
grp AS (
  SELECT
    user_id,
    event_date,
    event_date
      - INTERVAL '1 day' * (ROW_NUMBER() OVER (PARTITION BY user_id ORDER BY event_date))
      AS anchor
  FROM uniq_days
),
runs AS (
  SELECT
    user_id,
    MIN(event_date) AS start_day,
    MAX(event_date) AS end_day,
    COUNT(*) AS days_cnt
  FROM grp
  GROUP BY user_id, anchor
)
SELECT user_id, end_day AS third_day
FROM runs
WHERE days_cnt >= 3
ORDER BY user_id, third_day;