On Mon, Mar 01, 2004 at 09:21:32AM +0000, Richard Huxton wrote: > On Monday 01 March 2004 01:04, Stephen Howard wrote: > > I've got a moderately complex function defined which i then want to be > > > > able to test the value of, as well as select the value: > > > > select id, vector_cosine(document,'[ qw( foo,bar,baz )]') as threshold > > from search_vectorspace where threshold > 0 order by threshold desc; > > Can't be done that way, I'm afraid. The aliasing is defined as occuring after > the where clause has been evaluated. > > However, you can mark functions as immutable/stable/volatile which can allow > PG to cache the query results. See the manuals (CREATE FUNCTION) for details.
Or wrap the query in a another query, like: SELECT * from (select id, vector_cosine(document,'[ qw( foo,bar,baz )]') as threshold from search_vectorspace where threshold > 0) AS x order by threshold desc; Hope this helps, -- Martijn van Oosterhout <[EMAIL PROTECTED]> http://svana.org/kleptog/ > If the Catholic church can survive the printing press, science fiction > will certainly weather the advent of bookwarez. > http://craphound.com/ebooksneitherenorbooks.txt - Cory Doctorow
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