Set Analysis with date params

[#1]

Hi,

I have an issue with using Min, Max and Only in sets.  The following expression doesn't calculate the correct values: -

=Num(Sum(

{$<DATA_QUALITY = {1}, ORDER_STATUS -= {'refund'}, TEST_ORDER = {0}, VALID_ORDER = {1}, ITEM_TYPE-={'delivery','offer','delivery_surcharge'}, $(=Num([First Order Date])) = {">=$(=Min(Standard_Date))<=$(=Max(Standard_Date))"}> } $(=Only(Prefix))_$(=Only(Suffix))),$(=Only(Format)))

Basically the objective of the above script is to Sum items where the "First Order Date" is between the selected "Calendar Start and End Dates"