(some_manipulation_part), ifact as
   (  select date, sales_count from final_result_set
) select date_part('h',date )) as h  ,
         date_part('dow',date )) as day_of_week  ,
         count(sales_count)
  from final_result_set
  group by h, dow.

(some_manipulation_part), ifact as
(  select date, sales_count from final_result_set
) select date_part('h',date )) as h  ,
         date_part('dow',date )) as day_of_week  ,
         avg(sales_count)
  from final_result_set
  group by h, dow.