Re: ordered aggregates using WITHIN GROUP (was Re: can somebody execute this query on Oracle 11.2g and send result?)

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От Tom Lane
Тема Re: ordered aggregates using WITHIN GROUP (was Re: can somebody execute this query on Oracle 11.2g and send result?)
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Msg-id 4955.1264784222@sss.pgh.pa.us
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Ответ на ordered aggregates using WITHIN GROUP (was Re: can somebody execute this query on Oracle 11.2g and send result?)  (Alvaro Herrera <alvherre@commandprompt.com>)
Ответы Re: ordered aggregates using WITHIN GROUP (was Re: can somebody execute this query on Oracle 11.2g and send result?)  ("Jonah H. Harris" <jonah.harris@gmail.com>)
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Alvaro Herrera <alvherre@commandprompt.com> writes:
> So that's how Oracle supports ordered aggregates?  Interesting -- we
> just got that capability but using a different syntax.  Hmm, the
> SQL:200x draft also has <within group specification> which seems the
> standard way to do the ORDER BY stuff for aggregates ...  Should we
> change the syntax?

No.  The syntax we are using is also standard.  As best I can tell,
WITHIN GROUP means something different --- the spec only defines it
for rank functions (RANK | DENSE_RANK | PERCENT_RANK | CUME_DIST)
and it's basically a shorthand form of a window function call.
I find it doubtful that it's actually necessary in Oracle's version
of listagg ...
        regards, tom lane


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