My bad I used the wrong query:
SELECT ForcastUnitsTimesOMSCost, case when IsNUll(ForcastUnitsTimesOMSCost,0.00) <> 0 then SUM(CTCBOHAndWCSBOHTimesOMSCost/ForcastUnitsTimesOMSCost) else 0 end as Calculation
FROM MyTable
Where (CONVERT(date, GETDATE()) BETWEEN EventStartDate AND EventEndDate)
Group By ForcastUnitsTimesOMSCost