Lots of ORMS have an escape to SQL for querying, or you can choose to ignore the ORM for querying. As an example, ActiveRecord allows you to do this:

  Client.find_by_sql("
  SELECT * FROM clients
  INNER JOIN orders ON clients.id = orders.client_id
  ORDER BY clients.created_at desc
  ")

Which returns Client objects. Insert your own vastly more complex query above.