Re: Request for Patch Feedback: Lag & Lead Window Functions Can Ignore Nulls - Mailing list pgsql-hackers

From Nicholas White
Subject Re: Request for Patch Feedback: Lag & Lead Window Functions Can Ignore Nulls
Date
Msg-id CA+=vxNbP3kLHfSN839z0PRCTjRhpfWxb30ERx1pQohNhQ4261g@mail.gmail.com
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In response to Re: Request for Patch Feedback: Lag & Lead Window Functions Can Ignore Nulls  (Tom Lane <tgl@sss.pgh.pa.us>)
Responses Re: Request for Patch Feedback: Lag & Lead Window Functions Can Ignore Nulls  (Hitoshi Harada <umi.tanuki@gmail.com>)
List pgsql-hackers
Thanks - I've added it here: https://commitfest.postgresql.org/action/patch_view?id=1096 .

I've also attached a revised version that makes IGNORE and RESPECT UNRESERVED keywords (following the pattern of NULLS_FIRST and NULLS_LAST).

Nick


On 23 March 2013 14:34, Tom Lane <tgl@sss.pgh.pa.us> wrote:
Nicholas White <n.j.white@gmail.com> writes:
> The SQL standard defines a RESPECT NULLS or IGNORE NULLS option for lead,
> lag, [...]. This is not implemented in PostgreSQL
> (http://www.postgresql.org/docs/devel/static/functions-window.html)
> I've had a go at implementing this, and I've attached the resulting patch.
> It's not finished yet, but I was hoping to find out if my solution is along
> the right lines.

Since we're trying to get 9.3 to closure, this patch probably isn't
going to get much attention until the 9.4 development cycle starts
(in a couple of months, likely).  In the meantime, please add it to
the next commitfest list so we remember to come back to it:
https://commitfest.postgresql.org/action/commitfest_view?id=18

One comment just from a quick eyeball look is that we really hate
adding new keywords that aren't UNRESERVED, because that risks
breaking existing applications.  Please see if you can refactor the
grammar to make those new entries unreserved.

                        regards, tom lane

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