you can try like below
where Sales_Date>=$(vDate) and Sales_Date<=$(vDate)
you search like below
ps: $(vDate) is the variable or you can just use the actual date field also.
also check this extension
You don't have any prompting of dates that you do while running a load script directly.
However you can use "On Demand App for Big Data" (secret: it can be used for more than just big data) to create a selection app (doing the prompting/selection) which can be used as input to a template app that use the parameters from the selection app.