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List:       pgsql-hackers
Subject:    Re: [HACKERS] ordered aggregates using WITHIN GROUP (was Re: can
From:       Hitoshi Harada <umi.tanuki () gmail ! com>
Date:       2010-01-31 20:51:44
Message-ID: e08cc0401001311251q1f0a51bch3e273d90275b9133 () mail ! gmail ! com
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2010/2/1 Tom Lane <tgl@sss.pgh.pa.us>:
> Hitoshi Harada <umi.tanuki@gmail.com> writes:
>> In other words, the queries can be the same:
>
>> SELECT array_agg(val ORDER BY sk) FROM ...
>> SELECT array_agg(val) WITHIN GROUP (ORDER BY sk) FROM ...
>
> One more time: THOSE DON'T MEAN THE SAME THING.  If we ever get
> around to implementing the hypothetical set functions, we would
> be very unhappy to have introduced such a bogus equivalence.

I completely agree. Although Oracle's syntax can express ordered
aggregate, by introducing such syntax now it will be quite complicated
to implement hypothetical functions for those syntactic restrictions
and design in the future.


Regards,

-- 
Hitoshi Harada

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