What is the code of the product type with an average price higher than the average price of all products?
return product types ;return products of #1 ;return prices of #2 ;return average of #3 ;return average of #3 for each #1 ;return #1 where #5 is  higher than #4 ;return code of #6
['select', 'project', 'project', 'aggregate', 'group', 'comparative', 'project']