select r1.date,ifnull(r.id, 0) from
(
select date from login group by date
)as r1
left join
(
select l.date,count( l.user_id)as id
from login l
where l.user_id not in
(
select distinct l1.user_id
from login l1
where l1.date<l.date
)group by date
)as r
on r1.date=r.date