Обсуждение: coalesce a null to a char ?
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.
I get...
“ERROR: failed to find conversion function from unknown to text”
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@iol.ie
Galway Cathedral Recitals: http://www.galwaycathedral.org/recitals
------------------------------------------------------------------