- SELECT parts_id, description, serialnumber, trans_id, unit, sellprice, qty, assemblyitem, deliverydate, 'invoice' AS ioi FROM invoice UNION
- SELECT parts_id, description, serialnumber, trans_id, unit, sellprice, qty, FALSE AS assemblyitem, NULL AS deliverydate, 'orderitems' AS ioi FROM orderitems
+ SELECT parts_id, description, serialnumber, trans_id, unit, sellprice, qty, assemblyitem, deliverydate, 'invoice' AS ioi, id FROM invoice UNION
+ SELECT parts_id, description, serialnumber, trans_id, unit, sellprice, qty, FALSE AS assemblyitem, NULL AS deliverydate, 'orderitems' AS ioi, id FROM orderitems