message: fix(Query): output results with var names
diff: @@ -376,6 +376,14 @@ ResultSet::output(FILE* _fp)
  fprintf(_fp, "[empty result]\n");
  return;
  }
  +
  + fprintf(_fp, "%s", this->var_name[0].c_str());
  + for(int i = 1; i < this->true_select_var_num; i++)
  + {
  + fprintf(_fp, "\t%s", this->var_name[i].c_str());
  + }
  + fprintf(_fp, "\n");
  +
  for(long long i = (!this->useStream ? this->output_offset : 0LL); i < this->ansNum; i++)
  {
  if (this->output_limit != -1 && i == this->output_offset + this->output_limit)
  