@Test
  public void coalesceTest() {
    String[] expectedHeader = new String[] {"time", "level", "coalesce_attr2", "str"};
    String[] retArray =
        new String[] {
          "1970-01-01T00:00:00.040Z,l3,a,apricot,",
          "1970-01-01T00:00:00.040Z,l3,CCC,apricot,",
          "1970-01-01T00:00:00.020Z,l2,CCC,pineapple,",
          "1970-01-01T00:00:00.020Z,l2,zz,pineapple,",
          "1970-01-01T00:00:00.000Z,l1,d,coconut,",
          "1970-01-01T00:00:00.000Z,l1,c,coconut,",
        };
    tableResultSetEqualTest(
        "select time,level,coalesce(attr2, 'CCC', 'DDD') as coalesce_attr2,str from table0 order by num+1,attr1 limit 6",
        expectedHeader,
        retArray,
        DATABASE_NAME);
  }
In this IT, table has more than one TAGs and Attributes.
integration-test/src/test/java/org/apache/iotdb/relational/it/db/it/IoTDBMultiTAGsWithAttributesTableIT.java