@Test
  public void countDistinctTest() {
    String[] expectedHeader =
        new String[] {
          "device_id",
          "_col1",
          "_col2",
          "_col3",
          "_col4",
          "_col5",
          "_col6",
          "_col7",
          "_col8",
          "_col9",
          "_col10"
        };
    String[] retArray = new String[] {"d01,2,2,3,1,2,2,2,1,4,1,"};

    tableResultSetEqualTest(
        "select device_id, count(distinct s1), count(distinct s2), count(distinct s3), count(distinct s4), count(distinct s5), count(distinct s6), count(distinct s7), count(distinct s8), count(distinct s9), count(distinct s10) from table1 group by 1 order by 1",
        expectedHeader,
        retArray,
        DATABASE_NAME);
  }
In this Class, we construct the scenario using DistinctAccumulator for
AggregationFunctionDistinct. Other cases are covered by {@link IoTDBTableAggregationIT}.
integration-test/src/test/java/org/apache/iotdb/relational/it/query/recent/IoTDBTableAggregationFunctionDistinctIT.java