mustafasrepo opened a new pull request, #8356:
URL: https://github.com/apache/arrow-datafusion/pull/8356
## Which issue does this PR close?
<!--
We generally require a GitHub issue to be filed for all bug fixes and
enhancements and this helps us generate change logs for our releases. You can
link an issue to this PR using the GitHub syntax. For example `Closes #123`
indicates that this PR will close issue #123.
-->
Closes #.
## Rationale for this change
Currently we can rewrite group by expressions according to primary key.
Consider query below
```sql
SELECT ts, sn, SUM(amount) as sum1
FROM sales_global_with_pk
GROUP BY sn
```
normally, after aggregation only `sn` and `SUM(amount) as sum1` would be
available for output. However, given `sn` is `PRIMARY_KEY`, we know that each
`sn` value maps to a fixed `ts` value (e.g They are functionally depandant).
Hence, by treating query above as
```sql
SELECT ts, sn, SUM(amount) as sum1
FROM sales_global_with_pk
GROUP BY ts, sn
```
under the hood, we can output `ts` also at the end. However, this feature
was only available with `SQL` API. See
[discussion](https://github.com/apache/arrow-datafusion/pull/7040#discussion_r1275339446).
This PR brings this support to the dataframe API also. With this PR
following dataframe query can be executed given `col_id` is `PRIMARY_KEY`.
``` rust
// group by contains id column
let group_expr = vec![col_id.clone()];
let aggr_expr = vec![];
let df = df.aggregate(group_expr, aggr_expr)?;
// expr list contains id, name (e.g projection)
let expr_list = vec![col_id, col_name];
let df = df.select(expr_list)?;
```
<!--
Why are you proposing this change? If this is already explained clearly in
the issue then this section is not needed.
Explaining clearly why changes are proposed helps reviewers understand your
changes and offer better suggestions for fixes.
-->
## What changes are included in this PR?
<!--
There is no need to duplicate the description in the issue here but it is
sometimes worth providing a summary of the individual changes in this PR.
-->
## Are these changes tested?
Yes, most of the changes comes from either plan tests, or `.slt` test
<!--
We typically require tests for all PRs in order to:
1. Prevent the code from being accidentally broken by subsequent changes
2. Serve as another way to document the expected behavior of the code
If tests are not included in your PR, please explain why (for example, are
they covered by existing tests)?
-->
## Are there any user-facing changes?
<!--
If there are user-facing changes then we may require documentation to be
updated before approving the PR.
-->
<!--
If there are any breaking changes to public APIs, please add the `api
change` label.
-->
--
This is an automated message from the Apache Git Service.
To respond to the message, please log on to GitHub and use the
URL above to go to the specific comment.
To unsubscribe, e-mail: [email protected]
For queries about this service, please contact Infrastructure at:
[email protected]
