Github user marmbrus commented on a diff in the pull request:
https://github.com/apache/spark/pull/9406#discussion_r44198936
--- Diff:
sql/catalyst/src/main/scala/org/apache/spark/sql/catalyst/expressions/aggregate/Utils.scala
---
@@ -213,3 +216,178 @@ object Utils {
case other => None
}
}
+
+/**
+ * This rule rewrites an aggregate query with multiple distinct clauses
into an expanded double
+ * aggregation in which the regular aggregation expressions and every
distinct clause is aggregated
+ * in a separate group. The results are then combined in a second
aggregate.
--- End diff --
It would be really helpful if there was an example of what this rewrite
looks like here.
---
If your project is set up for it, you can reply to this email and have your
reply appear on GitHub as well. If your project does not have this feature
enabled and wishes so, or if the feature is enabled but not working, please
contact infrastructure at [email protected] or file a JIRA ticket
with INFRA.
---
---------------------------------------------------------------------
To unsubscribe, e-mail: [email protected]
For additional commands, e-mail: [email protected]
