Hi, I have a Materials Table that has a sub-table with different costs by Suppliers. Now I'm creating a Purchase Order and selecting the Material in the line item and I would like to populate the proper cost by matching the record with the Purchase order Supplier. can anyone help me with the proper select syntax ?

Thanks John. this is my data model looks like this :

and thanks to your help this works:

if not Materials.Id then
'PO Cost Each' := null
else
let x := this;
'PO Cost Each' := first(select 'Supplier Costs' where Materials.Id = x.Materials.Id and Supplier.Id = x.'Purchase Orders'.Suppliers.Id).Cost
end

Now I need help with the for loop syntax to change all the PO line items (Po Cost Each) to change when I update the PO supplier

thank you