Dividing

I have four sum statements in a procedure and I want to add two more fields that divide thismonthdeclines / thismonthsales, and prevmonthdeclines / premonthsales. I have tried a few ways and I just cant get the syntax right. Can someone help..


ALTER PROCEDURE dbo.sp_MTD_Declines

(@prevMonthStart datetime, @prevMonthEnd datetime, @thisMonthStart datetime, @thisMonthEnd datetime)

as

select

sum(case when O.orderdate between @prevMonthStart and @prevMonthEnd then D.orderlinetotal else 0 end ) as PrevMonthSales,

sum(case when O.orderdate between @thisMonthStart and @thisMonthEnd then D.orderlinetotal else 0 end ) as ThisMonthSales,

sum(case when O.orderdate between @prevMonthStart and @prevMonthEnd then case when O.orderstatus = 'CC Declined' then O.ordertotal end else 0 end) as PrevMonthDeclines,

sum(case when O.orderdate between @thisMonthStart and @thisMonthEnd then case when O.orderstatus = 'CC Declined' then O.ordertotal end else 0 end) as ThisMonthDeclines



from exigo_data_sync.Orders O INNER JOIN
exigo_data_sync.OrderDetail D ON O.OrderID = D.OrderID

where O.orderdate >= @prevMonthStart