message: add fixme for later
diff: @@ -114,6 +114,7 @@ unique_ptr<LogicalOperator> FlattenDependentJoins::PushDownDependentJoinInternal
  }
  if (aggr.groups.size() == correlated_columns.size()) {
  // we have to perform a LEFT OUTER JOIN between the result of this aggregate and the delim scan
  + // FIXME: this does not always have to be a LEFT OUTER JOIN, depending on whether aggr.expressions return NULL or a value
  auto left_outer_join = make_unique<LogicalComparisonJoin>(JoinType::LEFT);
  auto left_index = binder.GenerateTableIndex();
  auto delim_scan = make_unique<LogicalDelimGet>(left_index, delim_types);
  