Re: Add RESPECT/IGNORE NULLS and FROM FIRST/LAST options

Tom Lane <tgl@sss.pgh.pa.us>

From: Tom Lane <tgl@sss.pgh.pa.us>

To: Tatsuo Ishii <ishii@postgresql.org>

Cc: ojford@gmail.com, vik@postgresfriends.org, pgsql-hackers@postgresql.org, andrew@tao11.riddles.org.uk, david@fetter.org, krasiyan@gmail.com

Date: 2025-01-20T00:03:29Z

Lists: pgsql-hackers

Commits

Same data as JSON: GET /api/v1/messages/:b64id/commits the thread's linked commits as JSON, with link sources. API reference →

Fix coding style with "else".
- 20628b62e46e 19 (unreleased) landed
Fix multi WinGetFuncArgInFrame/Partition calls with IGNORE NULLS.
- 2d7b247cb414 19 (unreleased) landed
Fix Coverity issue reported in commit 2273fa32bce.
- dd766a441d69 19 (unreleased) landed
Use ereport rather than elog in WinCheckAndInitializeNullTreatment.
- 5f3808646f67 19 (unreleased) landed
Avoid uninitialized-variable warnings from older compilers.
- 71540dcdcb22 19 (unreleased) cited
Fix Coverity issues reported in commit 25a30bbd423.
- 2273fa32bce7 19 (unreleased) landed
Improve EXPLAIN's display of window functions.
- 8b1b342544b6 18.0 cited
Automatically generate node support functions
- 964d01ae90c3 16.0 cited

Tatsuo Ishii <ishii@postgresql.org> writes:
>> The latest version restricts it to lag, lead, first_value, last_value,
>> and nth_value. We can extend it in a subsequent patch if there's
>> demand?

> The restriction is required by the SQL standard. So I don't think we
> need to extend to other window functions.

The SQL spec does not believe that user-defined window functions are a
thing.  So its opinion on this point is useless.  I would think that
IGNORE NULLS is potentially useful for user-defined window functions,
and we should not be building anything that restricts the feature to
specific functions.

			regards, tom lane