Could you add the product type codes to the table please?
SELECT T1.product_name ,  sum ( T2.order_quantity ) ,T1.product_type_code FROM products AS T1 JOIN order_items AS T2 ON T1.product_id   =   T2.product_id GROUP BY T1.product_id
add product type codes to the table refers to including product_type_code in the SELECT statement;