Re: Greatest/Least functions?

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От Martijn van Oosterhout
Тема Re: Greatest/Least functions?
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Msg-id 20040823132908.GC4765@svana.org
обсуждение исходный текст
Ответ на Re: Greatest/Least functions?  (Mike Nolan <nolan@gw.tssi.com>)
Ответы Why does =ANY() need an extra cast when used on an array returned by a select?  (Frank van Vugt <ftm.van.vugt@foxi.nl>)
Список pgsql-general
On Sun, Aug 22, 2004 at 12:35:20PM -0500, Mike Nolan wrote:
> > > As far as I can tell, Postgres has no equivalent to greatest and least
> > > functions in Oracle.
> > Doesn't max/min() do that ? Note that I know nothing about
> > greatest/least in Oracle.
>
> No, max/min are aggregate functions.  Greatest allows you to select
> the largest of a series of terms.
>
> Here's a simple example:
>
> greatest(1,2,3,4,5,6) would return 6
>
> Here's a bit more useful one:
>
> greatest(field1,field2,field3) would return the largest value from the
> three supplied fields from the current row.

Postgresql does however have the 2-argument versions:

int4larger, int4smaller
floatlarger, floatsmaller

Not seen them mentioned much, but they're very useful... Of course,
after a while even:

int4larger( int4larger( field1, field2 ), int4larger( field3, field4 ) )

gets tiring.
--
Martijn van Oosterhout   <kleptog@svana.org>   http://svana.org/kleptog/
> Patent. n. Genius is 5% inspiration and 95% perspiration. A patent is a
> tool for doing 5% of the work and then sitting around waiting for someone
> else to do the other 95% so you can sue them.

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