WebReports Question

I created a web report that shows order detail information such as item, order qty and allocated quantity. It is straight forward and simply uses order header and order detail data objects.

I would also like to display the inventory quantity for the item on order detail. I added Inventory table and validated joins, but the report then runs indefinitely. Any tips on if this output is possible? Am I trying to do something that requires a subquery (which seem to be disabled in our version of web reports)?