Re: [HACKERS] Re: Subselects open issue Nr. 5

Vadim Mikheev <vadim@sable.krasnoyarsk.su>

From: "Vadim B. Mikheev" <vadim@sable.krasnoyarsk.su>
To: "Meskes, Michael" <meskes@topsystem.de>
Cc: Zeugswetter Andreas SARZ <Andreas.Zeugswetter@telecom.at>, "'pgsql-hackers@hub.org'" <pgsql-hackers@hub.org>, ocie@paracel.com
Date: 1998-02-16T11:56:37Z
Lists: pgsql-hackers
Meskes, Michael wrote:
> 
> Yes, and Oracle7 also.
> 
> I think with NULL values Andreas is right. The whole statement should be
> NULLed. That to me is the intuitive behaviour.

Not sure.
IMHO, any element, either with defined value or with undefined value (NULL),
can't be contained by empty set.

Hm, btw, just curious, what Informix returns for

select * from taba where (a,b) not in (<a select returning no row>);

having in taba tuples with (a,b) in

(NULL, a_value)
(NULL, NULL)

? 
Does it return all tuples except for (NULL,NULL) ?

Vadim