# File lib/arel/select_manager.rb, line 82
    def join relation, klass = Nodes::InnerJoin
      return self unless relation

      case relation
      when String, Nodes::SqlLiteral
        raise if relation.blank?
        from Nodes::StringJoin.new(@ctx.froms, relation)
      else
        from klass.new(@ctx.froms, relation, nil)
      end
    end