Horton

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

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

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From: Tom Lane <tgl@sss.pgh.pa.us>
To: Andrew Gierth <andrew@tao11.riddles.org.uk>
Cc: pgsql-hackers@postgresql.org, david@fetter.org, Oliver Ford <ojford@gmail.com>, Krasiyan Andreev <krasiyan@gmail.com>
Date: 2018-09-24T00:20:02Z
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 →

  1. Fix coding style with "else".

  2. Fix multi WinGetFuncArgInFrame/Partition calls with IGNORE NULLS.

  3. Fix Coverity issue reported in commit 2273fa32bce.

  4. Use ereport rather than elog in WinCheckAndInitializeNullTreatment.

  5. Avoid uninitialized-variable warnings from older compilers.

  6. Fix Coverity issues reported in commit 25a30bbd423.

  7. Improve EXPLAIN's display of window functions.

  8. Automatically generate node support functions

Andrew Gierth <andrew@tao11.riddles.org.uk> writes:
> "Tom" == Tom Lane <tgl@sss.pgh.pa.us> writes:
>  Tom> If you just think of recognizing FROM FIRST/LAST, you get nowhere
>  Tom> because that's still legal in other contexts. But if you were to
>  Tom> look for FROM followed by FIRST/LAST followed by
>  Tom> IGNORE/RESPECT/OVER, I think that could only validly happen in
>  Tom> this syntax.

> No; you need to go four tokens ahead in total, not three. Assuming
> nth_value is unreserved, then
>   select nth_value(x) from first ignore;
> is a valid query that has nth_value(x) as an expression, "first" as a
> table name and "ignore" as its alias.

No, because once IGNORE is a keyword, even unreserved, it's not legal
as an AS-less alias.  We'd be breaking queries like that no matter what.

(I know there are people around here who'd like to remove that
restriction, but it's not happening anytime soon IMO.)

			regards, tom lane