public boolean isDistinctLike() {
    List<AggregationDesc> aggregators = getAggregators();
    for (AggregationDesc ad : aggregators) {
      if (!ad.getDistinct()) {
        GenericUDAFEvaluator udafEval = ad.getGenericUDAFEvaluator();
        UDFType annot = AnnotationUtils.getAnnotation(udafEval.getClass(), UDFType.class);
        if (annot == null || !annot.distinctLike()) {
          return false;
        }
      }
    }
    return true;
  }
Checks if this grouping is like distinct, which means that all non-distinct grouping
columns behave like they were distinct - for example min and max operators.
ql/src/java/org/apache/hadoop/hive/ql/plan/GroupByDesc.java