binds_from_relation

# File activerecord/lib/active_record/connection_adapters/abstract/database_statements.rb, line 389
        def binds_from_relation(relation, binds)
          if relation.is_a?(Relation) && binds.empty?
            relation, binds = relation.arel, relation.bound_attributes
          end
          [relation, binds]
        end