On Thu, 06 Dec 2007 14:53:13 +0100
Cedric Boudin <cedric@dreamgnu.com> wrote:
> > What if boolean_column is NULL?
> >
> > btw set bolean_column= not bolean_column works "as expected".
> >
> > template1=# select (not 't'::boolean),(not 'f'::boolean),(not
> > NULL::boolean);
> >
> > ?column? | ?column? | ?column?
> > ----------+----------+----------
> > f | t |
> > (1 riga)
> If it was null before it has to be null afterwards (IMHO).
> If you don't want to have null,
> take care of it somewhere else but not here.
That is the "as expected" part.
The "case" case, other than being more verbose, do more than what I
would expect since all NULL are converted to t.
template1=# select case when NULL then 'f'::boolean else 't'::boolean
end;
case
------
t
(1 riga)
--
Ivan Sergio Borgonovo
http://www.webthatworks.it