Fix group by outputs. (#4128)

* Fix group by outputs.

* Add test.

* Fix format.

Co-authored-by: Sophie <84560950+Sophie-Xie@users.noreply.github.com>

src/graph/validator/GroupByValidator.cpp

@@ -20,6 +20,11 @@ Status GroupByValidator::validateImpl() {
  NG_RETURN_IF_ERROR(validateYield(groupBySentence->yieldClause()));
  NG_RETURN_IF_ERROR(groupClauseSemanticCheck());
 
+ for (auto* col : groupBySentence->yieldClause()->columns()) {
+ auto type = deduceExprType(col->expr());
+ outputs_.emplace_back(col->name(), std::move(type).value());
+ }
+
  return Status::OK();
 }
 
@@ -155,7 +160,6 @@ Status GroupByValidator::groupClauseSemanticCheck() {
  for (auto i = 0u; i < groupItems_.size(); ++i) {
  auto type = deduceExprType(groupItems_[i]);
  NG_RETURN_IF_ERROR(type);
- outputs_.emplace_back(aggOutputColNames_[i], std::move(type).value());
  }
  // check exprProps
  if (!exprProps_.srcTagProps().empty() || !exprProps_.dstTagProps().empty()) {

tests/tck/features/aggregate/Agg.feature

@@ -613,6 +613,21 @@ Feature: Basic Aggregate and GroupBy
  | sum |
  | 6 |
 
+ Scenario: Reference the output of group by
+ When executing query:
+ """
+ GO FROM "Tim Duncan" OVER * YIELD dst(edge) as dst, $$.player.age as age
+ | GROUP BY $-.dst YIELD (sum($-.age)+3) as age
+ | ORDER BY $-.age
+ """
+ Then the result should be, in order:
+ | age |
+ | 3 |
+ | 34 |
+ | 36 |
+ | 75 |
+ | 85 |
+
  Scenario: Error Check
  When executing query:
  """