1) For inventory, I'm trying to get the sum total of all inventory in warehouses where warehouse number in (100,200,300).  Additionally, my formula for getting the inventory is:
IM_ItemWarehouse.QuantityOnHand -IM_ItemWarehouse.QuantityOnPurchaseOrder -IM_ItemWarehouse.QuantityOnSalesOrder -IM_ItemWarehouse.QuantityInShipping

So, I'm wondering how to get a field that is a formula of other fields, but only where the inventory is in certain warehouses.

2) Also, I'm wondering how I can choose "Last Cost" in a vi job export.