message: fix(Query): ORDER BY var also SELECTed cause duplicate
diff: @@ -1365,6 +1365,17 @@ void GeneralEvaluation::getFinalResult(ResultSet &ret_result)
  vector<string> order_vars = query_tree.getOrderByVarset().vars;
  for (string var : order_vars)
  {
  + bool already_exist = false;
  + for (auto p : proj)
  + {
  + if (p.var == var)
  + {
  + already_exist = true;
  + break;
  + }
  + }
  + if (already_exist)
  + continue;
  QueryTree::ProjectionVar proj_var;
  proj_var.aggregate_type = QueryTree::ProjectionVar::None_type;
  proj_var.var = var;
  