Sort by sql query using a url param
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I have this huge ugly query below, i'd like to sort by it in a catalog view.  Thinking something like http://charitybuzz.dev:3000/catalog_items?&order=deals.  A million thank yous in advance for any comments or answers.    


    select 100 - round((current_price / item.estimated_price)*100) as percent, item.cached_thumbnail_url, item.item_id, it.name,
              ci.current_price, ci.close_date
               from item
               join catalog_item ci on ci.item_id = item.item_id
               join item_translations as it on (it.item_id = item.item_id)
               where  (100 - round((current_price / item.estimated_price)*100)) > 49 and 
               item.estimated_price > 0 and ci.current_price > 0 and ci.close_date > now() and item.active = 1 and ci.active = 1 and 
               (current_price / estimated_price) < 1
               order by (ci.close_date < DATE_ADD(now(), INTERVAL 17 hour))  and (item.estimated_price - current_price) desc
               limit 12