select uid,max(timestampdiff(day,t,next_t)+1) as maxt, round( max(timestampdiff(day,t,next_t)+1) * sum(cnt)/ (timestampdiff(day,min(t),max(t))+1) ,2) as avg_exam_cnt from(select uid,t,lead(t,1,0) over(partition by uid order by t) as next_t,cnt from( select uid,date(start_time) t,count(exam_id) as cn...