Re: Greatest/Least functions?

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От Mike Nolan
Тема Re: Greatest/Least functions?
Дата
Msg-id 200408221735.i7MHZLWv009715@gw.tssi.com
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Ответ на Re: Greatest/Least functions?  (Karsten Hilbert <Karsten.Hilbert@gmx.net>)
Ответы Re: Greatest/Least functions?  (Martijn van Oosterhout <kleptog@svana.org>)
Список pgsql-general
> > 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.

Writing a case statement to select the largest from among 3 or more
values gets a bit complicated.
--
Mike Nolan

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