---

UPDATE product 
SET quantity_in_stock = quantity_in_stock + (
    SELECT di.quantity 
    FROM delivery_item di
    WHERE di.product_id = product.product_id 
      AND di.delivery_id = (SELECT delivery_id FROM delivery WHERE document_number = 'DEL-001')
)
WHERE product_id IN (
    SELECT product_id 
    FROM delivery_item 
    WHERE delivery_id = (SELECT delivery_id FROM delivery WHERE document_number = 'DEL-001')
);