Re: MAX/MIN optimization via rewrite (plus query rewrites generally)
| От | Jim C. Nasby |
|---|---|
| Тема | Re: MAX/MIN optimization via rewrite (plus query rewrites generally) |
| Дата | |
| Msg-id | 20041111041734.GB56660@decibel.org обсуждение |
| Ответ на | MAX/MIN optimization via rewrite (plus query rewrites generally) (Mark Kirkwood <markir@coretech.co.nz>) |
| Ответы |
Re: MAX/MIN optimization via rewrite (plus query rewrites
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| Список | pgsql-hackers |
On Thu, Nov 11, 2004 at 11:48:49AM +1300, Mark Kirkwood wrote: > I am looking at implementing this TODO item. e.g. (max case): > > rewrite > SELECT max(foo) FROM bar > as > SELECT foo FROM bar ORDER BY foo DESC LIMIT 1 > if there is an index on bar(foo) Out of curiosity, will you be doing this in such a way that SELECT min(foo), max(foo) FROM bar will end up as SELECT (SELECT foo FROM bar ORDER BY foo ASC LIMIT 1), (SELECT ... DESC LIMIT 1) ? -- Jim C. Nasby, Database Consultant decibel@decibel.org Give your computer some brain candy! www.distributed.net Team #1828 Windows: "Where do you want to go today?" Linux: "Where do you want to go tomorrow?" FreeBSD: "Are you guys coming, or what?"
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