[jira] [Commented] (SPARK-37387) Allow nondeterministic expression in aggregate function

["Leona Yoda (Jira)" <ji...@apache.org>]

    [ https://issues.apache.org/jira/browse/SPARK-37387?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=17446329#comment-17446329 ] 

Leona Yoda commented on SPARK-37387:
------------------------------------

[~cloud_fan] I would like you to ask your opinion, I couldn't find the reason to set the rule, but there might be some reasons to prohibit this.

> Allow nondeterministic expression in aggregate function
> -------------------------------------------------------
>
>                 Key: SPARK-37387
>                 URL: https://issues.apache.org/jira/browse/SPARK-37387
>             Project: Spark
>          Issue Type: Improvement
>          Components: SQL
>    Affects Versions: 3.3.0
>            Reporter: Leona Yoda
>            Priority: Minor
>
> Nondeterministic expression in aggregate function is not allow in spark, so we cannot execute query like
> {code:java}
> SELECT COUNT(RANDOM());
> {code}
> and raise \{{nondeterministic expression ... should not appear in the arguments of an aggregate function. }}error message.
> [related code section|https://github.com/apache/spark/blob/master/sql/catalyst/src/main/scala/org/apache/spark/sql/catalyst/analysis/CheckAnalysis.scala#L298]
>  
> Hence other DB like PostgreSQL, we can call the SQL.
> {code:java}
> postgres=# SELECT COUNT(RANDOM());
>  count
> -------
>      1
> (1 row) {code}
>  
> I tried to remove the error message section, then I found spark could execute the query. 
> {code:java}
> scala> spark.sql("SELECT COUNT(RANDOM())").show()
> +-------------+
> |count(rand())|
> +-------------+
> |            1|
> +-------------+ {code}
>  
> It could be useful for spark users to be able to execute those kinds of queries because they can simply call
> {code:java}
> spark.sql("SELECT COUNT(DISTINCT(INPUT_FILE_NAME())) FROM table WHERE ...") {code}
> to find target files, for example.
>  



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