Re: array_agg() NULL Handling

From: Pavel Stehule <pavel(dot)stehule(at)gmail(dot)com>
To: Tom Lane <tgl(at)sss(dot)pgh(dot)pa(dot)us>
Cc: "David E(dot) Wheeler" <david(at)kineticode(dot)com>, Thom Brown <thom(at)linux(dot)com>, David Fetter <david(at)fetter(dot)org>, PostgreSQL Hackers <pgsql-hackers(at)postgresql(dot)org>
Subject: Re: array_agg() NULL Handling
Date: 2010-09-01 18:27:42
Message-ID: AANLkTi=vAhu6Q+579pXWaXe-6qyXvTA0+F7t3UA447MU@mail.gmail.com
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2010/9/1 Tom Lane <tgl(at)sss(dot)pgh(dot)pa(dot)us>:
> "David E. Wheeler" <david(at)kineticode(dot)com> writes:
>> On Sep 1, 2010, at 11:09 AM, Pavel Stehule wrote:
>>> Then you can eliminate NULLs with simple function
>
>> Kind of defeats the purpose of the efficiency of the aggregate.
>
> Well, you can build your own version of array_agg with the same
> implementation, except you mark the transition function as strict ...
>

I am checking this now, and it is not possible - it needs a some
initial value and there isn't possible to set a "internal" value.
probably some C coding is necessary.

Regards

Pavel

>                        regards, tom lane
>

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