merge_multi_values

# File activerecord/lib/active_record/relation/merger.rb, line 109
      def merge_multi_values
        lhs_wheres = relation.where_values
        rhs_wheres = values[:where] || []

        lhs_binds  = relation.bind_values
        rhs_binds  = values[:bind] || []

        removed, kept = partition_overwrites(lhs_wheres, rhs_wheres)

        where_values = kept + rhs_wheres
        bind_values  = filter_binds(lhs_binds, removed) + rhs_binds

        conn = relation.klass.connection
        bv_index = 0
        where_values.map! do |node|
          if Arel::Nodes::Equality === node && Arel::Nodes::BindParam === node.right
            substitute = conn.substitute_at(bind_values[bv_index].first, bv_index)
            bv_index += 1
            Arel::Nodes::Equality.new(node.left, substitute)
          else
            node
          end
        end

        relation.where_values = where_values
        relation.bind_values  = bind_values

        if values[:reordering]
          # override any order specified in the original relation
          relation.reorder! values[:order]
        elsif values[:order]
          # merge in order_values from relation
          relation.order! values[:order]
        end

        relation.extend(*values[:extending]) unless values[:extending].blank?
      end