Re: Review: listagg aggregate

Pavel Stehule <pavel.stehule@gmail.com>

From: Pavel Stehule <pavel.stehule@gmail.com>

To: Robert Haas <robertmhaas@gmail.com>

Cc: "David E. Wheeler" <david@kineticode.com>, Peter Eisentraut <peter_e@gmx.net>, Scott Bailey <artacus@comcast.net>, "pgsql-hackers@postgresql.org Hackers" <pgsql-hackers@postgresql.org>

Date: 2010-01-26T14:56:07Z

Lists: pgsql-hackers

2010/1/26 Robert Haas <robertmhaas@gmail.com>:
> On Tue, Jan 26, 2010 at 2:14 AM, Pavel Stehule <pavel.stehule@gmail.com> wrote:
>> 2010/1/25 Robert Haas <robertmhaas@gmail.com>:
>>> On Mon, Jan 25, 2010 at 2:27 PM, David E. Wheeler <david@kineticode.com> wrote:
>>>> On Jan 25, 2010, at 2:09 AM, Peter Eisentraut wrote:
>>>>> xmlagg -> concatenates values to form xml datum
>>>>> array_agg -> concatenates values to form array datum
>>>>> ??? -> concatenates values to form string datum
>>>>
>>>> concat_agg().
>>>
>>> I like that one...
>>
>> why is concat_agg better than listagg ?
>
> Because it doesn't make lists.
>
> Honestly, I don't love concat_agg() either - why should something need
> to have agg in the name just because it's an aggregate?  I think the
> most descriptive name would be something like
> concatenate_with_separator(), but that's kind of long.

This is never ending story :)

MySQL has function concate_ws - but this function has different semantic.

I thing so string_agg is short, and from one view consistent

Pavel

>
> ...Robert
>