Re: Avoiding evaluating functions twice.

> On Tuesday 04 October 2005 17:25, Tom Lane wrote:
> > han(dot)holl(at)informationslogik(dot)nl writes:
> > > select expensive_function(table) from table
> > > where expensive_function(table) is not null;
> > >
> > > Is there a way to avoid that expensive_function is evaluated twice (if
> > > it's not null) ?
> >
> > You can do something like this:
> >
> > select f from
> > (select expensive_function(table) as f from table offset 0) ss
> > where f is not null;

Why the offset 0?
--
Jim C. Nasby, Sr. Engineering Consultant jnasby(at)pervasive(dot)com
Pervasive Software http://pervasive.com work: 512-231-6117
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