merge_multi_values

# File activerecord/lib/active_record/relation/merger.rb, line 131
        def merge_multi_values
          if other.reordering_value
            # override any order specified in the original relation
            relation.reorder! other.order_values
          elsif other.order_values
            # merge in order_values from relation
            relation.order! other.order_values
          end

          relation.extend(*other.extending_values) unless other.extending_values.blank?
        end