Re: [GENERAL] question (or feature-request): over ( partition by ... order by LIMIT N)
| От | David Fetter |
|---|---|
| Тема | Re: [GENERAL] question (or feature-request): over ( partition by ... order by LIMIT N) |
| Дата | |
| Msg-id | 20100325211731.GA16362@fetter.org обсуждение исходный текст |
| Ответы |
Re: Re: [GENERAL] question (or feature-request): over (
partition by ... order by LIMIT N)
Re: Re: [GENERAL] question (or feature-request): over ( partition by ... order by LIMIT N) |
| Список | pgsql-hackers |
On Wed, Mar 24, 2010 at 06:31:59PM +0100, A. Kretschmer wrote: > Hello @all, > > I know, i can do: > > select * from (select ... row_number() over (...) ...) foo where > row_number < N > > to limit the rows per group, but the inner select has to retrieve > the whole set of records and in the outer select most of them > discarded. That sounds like the optimizer's falling down on the job. Would this be difficult to fix? Cheers, David. -- David Fetter <david@fetter.org> http://fetter.org/ Phone: +1 415 235 3778 AIM: dfetter666 Yahoo!: dfetter Skype: davidfetter XMPP: david.fetter@gmail.com iCal: webcal://www.tripit.com/feed/ical/people/david74/tripit.ics Remember to vote! Consider donating to Postgres: http://www.postgresql.org/about/donate
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