kosiew opened a new pull request, #14908:
URL: https://github.com/apache/datafusion/pull/14908
## Which issue does this PR close?
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- Closes #14884.
## Rationale for this change
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Why are you proposing this change? If this is already explained clearly in
the issue then this section is not needed.
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Currently, when passing a NULL value to to_char, it returns an empty string
instead of NULL. This behavior differs from PostgreSQL, which returns NULL when
given a NULL input. Aligning with PostgreSQL ensures consistency and expected
behavior for users relying on SQL standards.
## What changes are included in this PR?
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sometimes worth providing a summary of the individual changes in this PR.
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Modify to_char function implementation to return NULL when the input is NULL.
Update relevant test cases to validate the correct behavior.
Ensure consistent behavior across different data types.
## Are these changes tested?
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Yes, test cases have been added to check the NULL behavior of to_char.
Existing test cases have been updated where necessary.
Verified that the changes do not introduce regressions.
## Are there any user-facing changes?
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Users who previously received an empty string when calling to_char(NULL,
format) will now receive NULL, aligning with PostgreSQL behavior.
No breaking changes to public APIs, but behavior will be corrected to match
expected SQL standards.
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