Average of weight WITH price

gistfile1

select id, category, price, actual_weight , round(avg(actual_weight) over(partition by category rows between 2 preceding and 2 following),2),sum(actual_weight) over(partition by category rows between 2 preceding and 2 following), status from (select id, primary_category_id_reference as category, round(price_cents/100.0, 2) as price, weight as actual_weight, status from order_items where status between 5 and 8 and created_at > '2013-04-01' order by category, price_cents desc limit 1000) a;