docs: Clarify first_value usage in select vs aggregate#1348
Merged
timsaucer merged 3 commits intoapache:mainfrom Feb 12, 2026
Merged
docs: Clarify first_value usage in select vs aggregate#1348timsaucer merged 3 commits intoapache:mainfrom
timsaucer merged 3 commits intoapache:mainfrom
Conversation
Clarifies that aggregate functions like first_value must be used within .aggregate() and not .select(). Closes apache#1300.
7 tasks
nuno-faria
requested changes
Feb 8, 2026
| ) | ||
|
|
||
|
|
||
| def last_value( |
Contributor
There was a problem hiding this comment.
Should the same type of clarification be done on last_value as well?
python/datafusion/functions.py
Outdated
Contributor
There was a problem hiding this comment.
This example also needs to be changed right?
python/datafusion/functions.py
Outdated
Contributor
There was a problem hiding this comment.
Similar example as the first_value one.
Member
|
Thanks for the investigation and PR! I took the liberty of pushing a change that follows @nuno-faria 's request and I checked every other aggregate function while I was at it. I think just having correct usage solves the real problem rather than saying how to not use it. |
This file contains hidden or bidirectional Unicode text that may be interpreted or compiled differently than what appears below. To review, open the file in an editor that reveals hidden Unicode characters.
Learn more about bidirectional Unicode characters
Sign up for free
to join this conversation on GitHub.
Already have an account?
Sign in to comment
3 participants
Add this suggestion to a batch that can be applied as a single commit.This suggestion is invalid because no changes were made to the code.Suggestions cannot be applied while the pull request is closed.Suggestions cannot be applied while viewing a subset of changes.Only one suggestion per line can be applied in a batch.Add this suggestion to a batch that can be applied as a single commit.Applying suggestions on deleted lines is not supported.You must change the existing code in this line in order to create a valid suggestion.Outdated suggestions cannot be applied.This suggestion has been applied or marked resolved.Suggestions cannot be applied from pending reviews.Suggestions cannot be applied on multi-line comments.Suggestions cannot be applied while the pull request is queued to merge.Suggestion cannot be applied right now. Please check back later.
I investigated Issue #1300 and confirmed that the crash occurs because first_value (an aggregate function) is used inside .select(), which is not supported by the physical planner. This PR updates the docstring to explicitly warn users that first_value should be used with .aggregate() and not .select(). Closes #1300.