总之解决了问题，代码有点长：
select date,
(
select count() from
(
select date,type
from email e
where e.send_id in
(
select id from user
where user.is_blacklist=0
)
and e.receive_id in
(
select id from user
where user.is_blacklist=0
)
)as n_u1
where n_u1.date=normal_user.date and n_u1.type='no_completed'
)1.0/

count(type)
from
(
select date,type
from email e
where e.send_id in
(
select id from user
where user.is_blacklist=0
)
and e.receive_id in
(
select id from user
where user.is_blacklist=0
)

)as normal_user
group by date