mustafasrepo opened a new pull request, #8737:
URL: https://github.com/apache/arrow-datafusion/pull/8737
## Which issue does this PR close?
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Closes #.
## Rationale for this change
For window queries in the form `ROW_NUMBER() OVER(PARTITION BY <empty> ORDER
BY <expr>)`, we know that row numbers generated will consists of consecutive
numbers across table. Hence result of this expression can be treated as
`PRIMARY_KEY`. This enables us to execute queries in the form below
```sql
SELECT *
FROM (SELECT c1, c2, ROW_NUMBER() OVER() as rn
FROM aggregate_test_100
LIMIT 5)
GROUP BY rn
ORDER BY rn;
```
without this support query above should be re-written as
```sql
SELECT *
FROM (SELECT c1, c2, ROW_NUMBER() OVER() as rn
FROM aggregate_test_100
LIMIT 5)
GROUP BY rn, c1, c2 -- this line is the difference
ORDER BY rn;
```
to be able to execute.
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## What changes are included in this PR?
This PR adds ROW_NUMBER result as functional dependencies when it known that
its result will be unique across rows (when partition by expression is empty).
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## Are these changes tested?
Yes
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## Are there any user-facing changes?
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