@Override
  public List<List<String>> getInputColumnNamesList() {
    if (step.isInputRaw()) {
      List<String> inputColumnNames =
          SqlConstant.COUNT_IF.equalsIgnoreCase(aggregationFuncName)
              ? Collections.singletonList(inputExpressions.get(0).getExpressionString())
              : inputExpressions.stream()
                  .map(Expression::getExpressionString)
                  .collect(Collectors.toList());
      return Collections.singletonList(inputColumnNames);
    }

    List<List<String>> inputColumnNamesList = new ArrayList<>();
    groupedInputExpressions.forEach(list -> inputColumnNamesList.add(getInputColumnNames(list)));
    return inputColumnNamesList;
  }
Generates the parameter part of the output column name.

<p>Example:

<p>Full output column name -> count_if(root.*.*.s1, 3)

<p>The parameter part -> root.*.*.s1, 3
iotdb-core/datanode/src/main/java/org/apache/iotdb/db/queryengine/plan/planner/plan/parameter/CrossSeriesAggregationDescriptor.java