Return the average price for each product type.
SELECT product_type_code ,  avg(product_price) FROM products GROUP BY product_type_code
SELECT product_type_code ,  avg(product_price) FROM products GROUP BY product_type_code
[{'product_type_code': 'Clothes', 'avg(product_price)': 715.5366666666666}, {'product_type_code': 'Hardware', 'avg(product_price)': 796.0416666666666}]