ы пишешьNOT EXISTS в Ареле? У меня проблемы с переводом этого запроса на Arel:

SELECT * FROM deals 
WHERE NOT EXISTS (
   SELECT 1 FROM reward_deals 
   WHERE reward_deals.deal_id = deal.id 
   AND NOT (
      reward_deals.awarding_type = 'deal' 
      AND reward_deals.deal_id = reward_deals.awarding_id
   )
 )