Repository navigation
Support Grouping functions with Group By CUBE/ROLLUP/GROUPING SETS #5647
Description
Is your feature request related to a problem or challenge? Please describe what you are trying to do.
PostgreSQL, SparkSQL and Oracle support using GROUPING functions to specify the null is from subtotal or from original
data.
https://www.postgresql.org/docs/15/functions-aggregate.html#FUNCTIONS-HYPOTHETICAL-TABLE
Databricks SparkSQL
https://docs.databricks.com/sql/language-manual/functions/grouping.html
Oracle
https://oracle-base.com/articles/misc/rollup-cube-grouping-functions-and-grouping-sets#grouping
Describe the solution you'd like
Describe alternatives you've considered
Additional context
Activity
mingmwang commentedon Mar 21, 2023
I'm working on it now.
l1t1 commentedon Apr 26, 2024
where is the document of these features?
bgjackma commentedon Sep 18, 2024
take
bgjackma commentedon Sep 18, 2024
I don't think this works as a aggregate function in the physical plan. It depends on the grouping rather than the data, so the current abstraction doesn't have access to the necessary information.
I think this case (along with GROUPING_ID, any others?) will need special handling in
GroupHashedAggregateStream.alamb commentedon Sep 19, 2024
Note there is a PR with a proposed implementation from @JasonLi-cn in #10208
bgjackma commentedon Sep 19, 2024
Thanks for the heads up, that's helpful however I think I have a slightly nicer solution that doesn't force changes on existing accumulators.
eejbyfeldt commentedon Sep 20, 2024
Note that @mingmwang (the author of this ticket) had an alternative approach here: #5749 but it seems like it was never pushed above the finish line. It is based on how it is implemented in Spark.
What is good with that approach is that it also helps address other issues in the current implementation of grouping sets. For example the current implementation will produce incorrect results when there are null values in the actual columns. I also looked into creating PR for only fixing that bug in a similar way to #5749 but need to spend some more time on it.