declare @ttDate1 datetime
declare @ttDate2 datetime

set @ttDate1='02/08/2002 00:00:00'
set @ttDate2='02/08/2002 23:59:00'

SELECT  avg(datediff(mi,t1.enteror,t1.exitor)) as timeused,
        count(t2.dcode) as proccnt,t2.dcode, 
	(select isnull(avg(cocasedata.itemunitcost * coCaseData.ActualQty),0)
		FROM dbo.meetings t3 INNER JOIN
                dbo.meetproc t4 ON t3.meetingnumber = t4.meetingnumber INNER JOIN
                dbo.cocasedata ON t3.meetingnumber = dbo.cocasedata.meetingnumber
		where t3.begintime between @ttDate1 and @ttDate2 
		AND t4.dcode = t2.dcode) as avgResCost
FROM   dbo.meetings t1 INNER JOIN
       dbo.meetproc t2 ON t1.meetingnumber = t2.meetingnumber
where t1.begintime between @ttDate1 and @ttDate2
group by dcode