Re: Request for Patch Feedback: Lag & Lead Window Functions Can Ignore Nulls

Nicholas White <n(dot)j(dot)white(at)gmail(dot)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