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https://issues.apache.org/jira/browse/SPARK-54833?page=com.atlassian.jira.plugin.system.issuetabpanels:all-tabpanel
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ASF GitHub Bot updated SPARK-54833:
-----------------------------------
Labels: pull-request-available (was: )
> MODE() WITHIN GROUP ORDER BY displays incorrect sort direction in SQL string
> ----------------------------------------------------------------------------
>
> Key: SPARK-54833
> URL: https://issues.apache.org/jira/browse/SPARK-54833
> Project: Spark
> Issue Type: Bug
> Components: SQL
> Affects Versions: 3.4.0, 4.2.0
> Reporter: lixiaolong04
> Priority: Minor
> Labels: pull-request-available
>
> {{MODE() WITHIN GROUP (ORDER BY ...)}} executes correctly for both {{ASC}}
> and {{{}DESC{}}}, but the SQL string representation displays an incorrect or
> missing sort direction.
> This causes a mismatch between the executed semantics and the displayed SQL
> In {{{}Mode.scala{}}}, the SQL string representation is generated based on
> {{{}reverseOpt{}}}:
> [https://github.com/apache/spark/blob/e316d28be78d23b03f8615bda3919d2d212aeb17/sql/catalyst/src/main/scala/org/apache/spark/sql/catalyst/expressions/aggregate/Mode.scala#L173-L180]
> {code:java}
> override def sql(isDistinct: Boolean): String = {
> reverseOpt.map {
> reverse =>
> if (reverse) {
> s"$prettyName() WITHIN GROUP (ORDER BY ${child.sql} DESC)"
> } else {
> s"$prettyName() WITHIN GROUP (ORDER BY ${child.sql})"
> }
> }.getOrElse(super.sql(isDistinct))
> }{code}
>
> However, {{reverseOpt}} is derived from {{withOrderingWithinGroup}} and does
> not directly reflect the original {{ORDER BY}} direction. As a result, the
> SQL string can display a reversed or missing sort direction, even though the
> execution semantics are correct.
> *Proposed Fix*
> Swap the {{ASC}} / {{DESC}} handling in {{sql()}} so that the displayed ORDER
> BY direction matches the actual execution semantics
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