Count based on subset of data - sql

Question

I have a join to a table and I want to include all users who have a record after a certain date, but to only include records after another date in the count.
Here is my SQL :
select a.userid, count(ce.codeentryid)
from [account] a
inner join [profile] p
on a.userid = p.userid
inner join codesentered ce
on a.userid = ce.userid and ce.entrydate > '2011-01-01 00:00:00'
where a.camp = 0
group by a.userid
order by a.userid
So here I want to view a list of all users who have entered a code after 1st Jan 2011, but to only include in the count codes entered after 1st Jan 2013. How would I do this?
EDIT : So this would give me all users who have entered a code after 01/01/2011, but only include codes entered after 01/01/2013 in the count?
select a.userid, count(CASE WHEN ce.entrydate > '2013-01-01 00:00:00' THEN 1 ELSE 0 END)
from [account] a
inner join [profile] p
on a.userid = p.userid
inner join codesentered ce
on a.userid = ce.userid and ce.entrydate > '2011-01-01 00:00:00'
where a.camp = 0
group by a.userid
order by a.userid

Answer 1

Remove the date condition from the ON clause, and use this in the SELECT clause instead of COUNT(ce.codeentryid):
SUM(CASE WHEN ce.entrydate > '2011-01-01 00:00:00' THEN 1 ELSE 0 END)

Answer 2

Your question doesn't make sense, because using two dates is redundant. Unless I assume that you want users whose first count is after 2011-01-01 and then only count what happens after 2013-01-01.
If that is what you want, then use a having clause:
select a.userid, sum(CASE WHEN ce.entrydate > '2013-01-01 00:00:00' THEN 1 ELSE 0 END)
from [account] a inner join
[profile] p
on a.userid = p.userid inner join
codesentered ce
on a.userid = ce.userid
where a.camp = 0
group by a.userid
having min(ce.entrydate) > '2011-01-01 00:00:00'
order by a.userid;
Note that count(CASE WHEN ce.entrydate > '2013-01-01 00:00:00' THEN 1 ELSE 0 END) is the same as count(*). count() counts non-null values. Use sum() instead.