jackylee

cc @PHILO-HE @rui-mo

> @jackylee-ch, I meant we can only update the doc for this function without `limit` arg, as I note `limit` arg is not considered in this pr. Right? Except this,...

Hm, it is another problem. Here is the reproduce code. ```SQL create table test_int(a int) using parquet; insert overwrite test_int values(0); -- this returns null as expected. select a /...

Hm, it is the problem for divide/mod with decimal, I didn't fix it in (https://github.com/oap-project/arrow/pull/186)

The main reason for this problem is the iterator defined in ColumnarHashAggregateExec is invalid. Its hasNext would return different value if we called it twice without calling next func. And...