Re: feature request ?

On Fri, 25 Jun 2004 08:16:47 +0400, sad <sad@bankir.ru> wrote:

> > Very simply, a boolean may have to values: true or false.  It's also
> > possible that it's not been set to anything (NULL).

> really ?
> what about   (13 < NULL)::BOOL

Per the semantics of NULL, 13 is neither greater than nor less than
NULL.  NULL is the *unknown* value; it's impossible to meaningfully
compare it to anything else. Try (NULL = NULL)::boolean. It's NULL,
also.

Since no value, including NULL, is in any way definitively comparable
to NULL -- the unknown value -- comparing to NULL results in ...
unknown.

Otherwise known as NULL.

/rls

--
:wq