UPDATE C_Order o
SET IsDelivered = 'N'
WHERE o.IsDelivered = 'Y'
  AND o.processed = 'Y'
  AND (o.issotrx = 'Y' OR (o.issotrx = 'N' AND (SELECT dt.isreturn FROM c_doctype dt WHERE o.c_doctypetarget_id = dt.c_doctype_id) = 'Y'))
  AND EXISTS (SELECT 1
              FROM c_orderline ol
              WHERE o.c_order_id = ol.c_order_id
                AND ol.c_order_discount_id IS NULL                     
                AND ol.QTYORDERED <> ol.QTYDELIVERED
              );