On Tue, Apr 1, 2008 at 6:04 PM, Stephan Szabo <[EMAIL PROTECTED]> wrote: > On Tue, 1 Apr 2008, Raphael Bauduin wrote: > > > The 2 following statements don't give the same result. I expected the > > second ti give the exact same result as the first one. > > If any entree_id can be NULL they aren't defined to give the same result. > > EXCEPT is defined in terms of duplicates based on distinctness, and for > example (1 is distinct from 1) is false, (1 is distinct from NULL) is true > and (NULL is distinct from NULL) if false. > > NOT IN is defined in terms of equality, and for example, (1=1) is true, > (1=NULL) is unknown and (NULL=NULL) is unknown. >
My problem came from 2 entries in the table postes that had an entree_id NULL Thanks for your fast answer, it has helped me spot the problem! Raph -- Web database: http://www.myowndb.com Free Software Developers Meeting: http://www.fosdem.org -- Sent via pgsql-sql mailing list (pgsql-sql@postgresql.org) To make changes to your subscription: http://www.postgresql.org/mailpref/pgsql-sql
