Re: filtering after join

On Wed, Jan 25, 2006 at 06:27:33PM +0100, andrew wrote:
> I want to use a UDF to filter tuples t that are generated after a join.
> More specifially, I have a UDF foo(record), which computes a value for
> a given tuple.  I can do the filtering before the join. e.g.:
> 
> select * from A, B where foo(A)<2 and A.a=B.b;
> 
> But I want to apply foo() to the tuples generated by the join
> operation. How can I do that?

Is this what you're looking for?

select *
from (select * from A, B where A.a = B.b) as s
where foo(s) < 2;

-- 
Michael Fuhr