Hi Michelle! Try switching your Lookup function to this:
lookup(min([Order Date]),0) >= [Start Date] AND
lookup(min([Order Date]),0) <= [End Date]
Remove the existing Lookup filter, put this one in, and include only TRUE. You may have to adjust the signs to accommodate how you want to handle the endpoints of the range.
I think you're looking for this:
IF MIN([Order Date])>= [Start Date]
AND MAX([Order Date]) <= [End Date]
THEN lookup(MIN([Order Date]),0) END
The LOOKUP() aggregation can be any non-additive aggregate: MIN(), MAX(), AVG(), etc. It doesn't matter because at the day level MIN and MAX are the same.
Thanks! this seems to work!!