Re: Functions returning sets - Mailing list pgsql-hackers

From Stephan Szabo
Subject Re: Functions returning sets
Date
Msg-id Pine.BSF.4.21.0105201144170.54047-100000@megazone23.bigpanda.com
Whole thread Raw
In response to Re: Functions returning sets  (Don Baccus <dhogaza@pacifier.com>)
List pgsql-hackers
On Sun, 20 May 2001, Don Baccus wrote:

> At 10:55 AM 5/20/01 -0700, Stephan Szabo wrote:
> > Can the IN always get written as a
> >join and is it always better to do so?
> 
> Nope:
> ...
> A better question, I guess, is if it is always better to write
> it as a join if the left hand operand is a table column and
> the right hand operand a rowset.

Well I was assuming we were talking about the subquery case
in general :)

It might be a problem with subqueries with set value functions
and parameters passed down from the outer tables:
select * from blah whereblah.val1 in  (select count(*) from blah2 where blah2.val2=blah.val2   group by blah2.val3);



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