text: -- 20
  INSERT INTO northwind.order_details (order_id, product_id, quantity, unit_price, discount, status_id, date_allocated, purchase_order_id, inventory_id)
  	VALUES (69, 80, 15.0000, 15.0000, 0, 2, NULL, NULL, 129);
  -- 21
  INSERT INTO northwind.order_details (order_id, product_id, quantity, unit_price, discount, status_id, date_allocated, purchase_order_id, inventory_id)
  	VALUES (69, 80, 15.0000, 15.0000, 0, 2, NULL, NULL, 129), (69, 80, 15.0000, 15.0000, 0, 2, NULL, NULL, 129);
  -- 22
  UPDATE northwind.order_details SET discount = 15;
  -- 23
  UPDATE northwind.order_details SET discount = 30 WHERE unit_price < 10.0000;
  -- 24
  UPDATE northwind.order_details SET discount = 45 WHERE unit_price > 10.0000 AND id BETWEEN 29 AND 40;
  SELECT * FROM northwind.order_details WHERE unit_price > 10.0000 AND id BETWEEN 30 AND 40;
  -- 25
  DELETE FROM northwind.order_details WHERE unit_price < 10.0000;
  -- 26
  DELETE FROM northwind.order_details WHERE unit_price > 10.0000;
  -- 27
  TRUNCATE northwind.order_details;