> On Tuesday 04 October 2005 17:25, Tom Lane wrote: > > [EMAIL PROTECTED] 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 [EMAIL PROTECTED] Pervasive Software http://pervasive.com work: 512-231-6117 vcard: http://jim.nasby.net/pervasive.vcf cell: 512-569-9461 ---------------------------(end of broadcast)--------------------------- TIP 4: Have you searched our list archives? http://archives.postgresql.org
