Show all product names and the total quantity ordered for each product name.
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
show all product names refers to SELECT product_name; total quantity ordered for each product name refers to SUM(product_quantity); need to join tables Order_items and Products on product_id;