Show all product names and the total quantity ordered for each product name.
create table products (product_name varchar, product_id varchar, PRIMARY KEY (product_name)); create table order_items (product_quantity integer, product_id varchar, PRIMARY KEY (product_quantity))
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