Re: idea - new aggregates median, listagg

From: Robert Haas <robertmhaas(at)gmail(dot)com>
To: Pavel Stehule <pavel(dot)stehule(at)gmail(dot)com>
Cc: David Fetter <david(at)fetter(dot)org>, PostgreSQL Hackers <pgsql-hackers(at)postgresql(dot)org>
Subject: Re: idea - new aggregates median, listagg
Date: 2009-12-16 14:45:30
Message-ID: 603c8f070912160645w3550f63i6a9d82fe0c98d4c1@mail.gmail.com
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On Wed, Dec 16, 2009 at 1:36 AM, Pavel Stehule <pavel(dot)stehule(at)gmail(dot)com> wrote:
>>> b) function listagg (it is analogy of group_concat from MySQL) - it
>>> should simplify report generating and some other
>>
>> This is redundant, as it's equivalent to array_to_string(array_agg()).
>
> when I implement it in orafce - the almost all code was parameters
> checking. Implementation is trivial, because important part of work
> was done with array_agg support. It is wrapper over stringInfo.
>
>>
>> If it's done as syntactic sugar over that, it's fine.  If it's a
>> separate implementation, it's a bad idea.  Probably best as an
>> optional module of some kind
>
> I am not sure if implementation as syntactic sugar is best. It needs
> parser changes.

I don't think this is important enough to change the parser for it. I
don't see a concrete proposal for syntax here, but it seems like the
standard function call syntax should be adequate.

...Robert

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