What are the different product names, and what is the sum of quantity ordered for each product?
SELECT T2.product_name ,  sum(T1.product_quantity) FROM Order_items AS T1 JOIN Products AS T2 ON T1.product_id  =  T2.product_id GROUP BY T2.product_name
Farklı ürün adları nelerdir ve her ürün için sipariş edilen miktarın toplamı nedir?