select
	PREV_MONTH_COUNT =
		sum(case when PRIOR_MONTH_INDICATOR = 1  then MONTH_COUNT else 0 end),
	PREV_MONTH_AVG_ORDER_TOTAL =
		sum(case when PRIOR_MONTH_INDICATOR = 1  then MONTH_AVG_ORDER_TOTAL else 0 end),
	CURR_MONTH_COUNT =
		sum(case when PRIOR_MONTH_INDICATOR <> 1 then MONTH_COUNT else 0 end),
	CURR_MONTH_AVG_ORDER_TOTAL =
		sum(case when PRIOR_MONTH_INDICATOR <> 1 then MONTH_AVG_ORDER_TOTAL else 0 end)
from
	(
	select
		[START_OF_MONTH]		=
			dateadd(mm,datediff(MM,0,orders.orderdate),0),
		PRIOR_MONTH_INDICATOR		=
			max(
			case
			when	-- First day of month for order
				dateadd(mm,datediff(MM,0,orders.orderdate),0) =
				-- First day of last month
				dateadd(mm,datediff(MM,0,getdate())-1,0)
			then 1
			else 0 end),
		MONTH_COUNT		= count(*),
		MONTH_AVG_ORDER_TOTAL	= avg(orders.ordertotal)
	from
		orders
	where
		-- Select orders for current and prior month
		orders.orderdate >= dateadd(mm,datediff(MM,0,getdate())-1,0)
	group by
		-- Start of Month
		dateadd(mm,datediff(MM,0,orders.orderdate),0)
	) a