You have several options and the details of each depend on your database.
You, or a script, can enter find mode and use ">1" in your inventory total field to find all records with a value
You might have a value list of ProductID's where it's a conditional value list limited only to those products that have available inventory.
A portal might be used to list products with available inventory. If you use a portal, a portal filter or the relationship might be set up to limit the records shown to those on hand. If you use a relationship, the quantity on hand field needs to be a stored and indexed field--something that is often not the case with such a field as it may be summing up data in multiple records in another table.
I am using the last one with a portal however haven't been able to get the "InvAvailable to work" the field is stored and indexed. What would the formula be after
PriceBook_e::gSearchField= Left (Inventory_Items_4select::Code_PB_pk; Length (PriceBook_e::gSearchField ) )
???and or is >1 (PriceBook_e::gSearchFieldQty ) )
... AND Inventory_Items_4select::InvAvailable > 0
I am assuming you don't want to omit items with 1 item available.
... AND Inventory_Items_4select::InvAvailable > PriceBook_e::gSearchFieldQty
If you want the user to specfiy the minimum quantity on hand as part of the filter.