Re: Need some magic with alternative rows - Mailing list pgsql-sql

On 7 jun 2008, at 05.04, Andreas wrote:
> Is there a way to remove the default-rows if there exists a fk<>0  
> row that has the same group_nr ?

Yes, use a correlated sub-query:

SELECT * FROM mytab m1
WHERE fk = 994010 OR (class_nr = 40 AND fk = 0 AND NOT EXISTS (SELECT  
1 FROM mytab m2 WHERE m2.group_nr=m1.group_nr AND fk <> 0));




Sincerely,

Niklas Johansson