Try to add HAVING clause

...
HAVING  sum(c.actualqty) < @UserLimit

>In the query below I am returning all rows of supply items used for a given date range. My ultimate goal is to limit the query to return only rows where the TotalUsed column calculate to less than some number passed by the user. I don't know how to do that part of it.
>
>

>declare @tiDept as int
>declare @DateFrom as datetime
>declare @DateTo as DateTime
>declare @tiMinUsage as int
>
>set @tiDept = 1
>set @dateFrom = '10/01/2001 00:00'
>set @dateTo =   '10/01/2002 23:59'
>
>
>SELECT  i.primedesc, i.catalogno, sum(c.actualqty) as TotalUsed,
>	(Select isnull(dbo.coinv.medication,0)  from dbo.coinv where invid=i.invid) as Medication
>        FROM    dbo.cocasedata c INNER JOIN
>        dbo.coinv i ON c.linkedid = i.invid INNER JOIN
>        dbo.meetings ON c.meetingnumber = dbo.meetings.meetingnumber
>WHERE   (dbo.meetings.iscompleted = 1)
>AND     dbo.meetings.begintime between @dateFrom and @dateTo
>group by invid,primedesc,catalogno
>