Re: coalesce a null to a char ?

From: Raymond O'Donnell <rod(at)iol(dot)ie>
To: "Gauthier, Dave" <dave(dot)gauthier(at)intel(dot)com>
Cc: "pgsql-general(at)postgresql(dot)org" <pgsql-general(at)postgresql(dot)org>
Subject: Re: coalesce a null to a char ?
Date: 2009-04-06 22:27:15
Message-ID: 49DA81C3.7000503@iol.ie
Views: Raw Message | Whole Thread | Download mbox | Resend email
Thread:
Lists: pgsql-general

On 06/04/2009 22:55, Gauthier, Dave wrote:
> How can I do this....
>
> selcet coalesce((select 'y' from foo where name = f.name),'n') from foo f where...
>
> So the query returns a "y" or "n" depending on whether or not the subquery is null.

Are you sure that the subquery is returning any rows? Try something like
this instead (not tested):

select
case
when exists(select 1 from foo where name = f.name) then 'y'
else 'n'
end
from foo....

Ray.

------------------------------------------------------------------
Raymond O'Donnell, Director of Music, Galway Cathedral, Ireland
rod(at)iol(dot)ie
Galway Cathedral Recitals: http://www.galwaycathedral.org/recitals
------------------------------------------------------------------

In response to

Browse pgsql-general by date

  From Date Subject
Next Message Kashmir 2009-04-06 22:32:17 Re: user defined aggregate for percentile calculations
Previous Message Kevin Grittner 2009-04-06 22:05:33 Re: tsearch2 dictionary for statute cites