Re: constraint -- one or the other column not null

On Wed, Sep 06, 2006 at 09:59:03AM +0200, Ivan Sergio Borgonovo wrote:
> You can write a xor function. At least in 7.4, that I'm currently using, there is no xor operator.

Ah, but there's is, but it's in disguise:

test=# select true <> true, true <> false, false <> true, false <> false;
?column? | ?column? | ?column? | ?column?
----------+----------+----------+----------
f | t | t | f
(1 row)

Hope this helps,
--
Martijn van Oosterhout <kleptog(at)svana(dot)org> http://svana.org/kleptog/
> From each according to his ability. To each according to his ability to litigate.