Re: is it possible to make this faster?

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От Steinar H. Gunderson
Тема Re: is it possible to make this faster?
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Msg-id 20060525210850.GA20274@uio.no
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Ответ на Re: is it possible to make this faster?  ("Merlin Moncure" <mmoncure@gmail.com>)
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On Thu, May 25, 2006 at 04:54:09PM -0400, Merlin Moncure wrote:
>>  select a,b,(select c from t t2 order by c desc where t1.a=t2.a and
>>  t1.b=t2.b)
>>  from t t1 group by a,b;
> this came out to a tie with the group by approach, although it
> produced a different (but similar) plan.  we are still orders of
> magnitude behind mysql here.

Actually, it _should_ produce a syntax error -- it's missing a LIMIT 1 in the
subquery.

/* Steinar */
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Homepage: http://www.sesse.net/

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