select uid, max(timestampdiff(day, last_date, cur_date) + 1) as days_window, round( count(exam_id) / ( timestampdiff(day, min(cur_date), max(cur_date)) + 1 ) * max(timestampdiff(day, last_date, cur_date) + 1), 2 ) as avg_count from ( select uid, exam_id, date(start_time) as cur_date, lag(date(start_...