select round((count(distinct d.user_id))/count(distinct c.user_id) ,3) as p from login c left join ( select a.user_id, client_id, date, first_day, second_day from login a, ( select user_id, min(date) as first_day, date_add(min(date), interval 1 day) as second_day from login group by user_id ) b wher...