eejbyfeldt opened a new pull request, #12571:
URL: https://github.com/apache/datafusion/pull/12571
## Which issue does this PR close?
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Closes #12570
## Rationale for this change
Currently we produce incorrect results when combining grouping sets and
columns containing null values.
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the issue then this section is not needed.
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## What changes are included in this PR?
The bug is by introducing an internal column `grouping_id` when using
grouping sets. This extra column makes sure that we create different groups for
the nulls from the grouping sets and the data.
This approach is based on how it is implemented in Spark and has previously
been proposed here: https://github.com/apache/datafusion/pull/5749 Note that
this change is smaller in scope and limit the existence of the `grouping_id` to
the physical plan. This is done so we end up with a smaller PR that is easier
to review. But we might want to follow up and extend it to the logical plan an
use it to implement the grouping function (#5647) in a similar manner to what
is done in Spark.
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## Are these changes tested?
Existing and new sqllogictests.
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## Are there any user-facing changes?
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