>>SELECT SUM(CAST(DATETIME1 - DATETIME2 AS int)) AS NUMDAYS >>>>>
DECLARE @Test TABLE (Fld1 datetime, Fld2 datetime) DECLARE @i int SET @i = 0 WHILE @i < 1000 BEGIN INSERT INTO @Test VALUES (GETDATE()+@i, GETDATE()+@i*20) SET @i = @i +1 END set statistics time on SELECT SUM(cast(Fld2-Fld1 as int)) FROM @Test SELECT SUM(DATEDIFF(dd,Fld1,Fld2)) FROM @Test