What I am asking is somewhat similar to this discussion.
In “Sales Order Item” and “Purchase Order Item”, the default is set up to show the actual price for each item entered (based on Price List and Item Code). What I am trying to show is the unique ID of the “Item Price” object, usually ITEM-PRICE-XXXXX.
I understand about using Custom Script and having customized field, but what function is required to search an object (Item Price) based on two objects (Item Code and Price List)? add_fetch can only get data from one object.