Re: [HACKERS] Re: Subselects open issue Nr. 5 - Mailing list pgsql-hackers

From Vadim B. Mikheev
Subject Re: [HACKERS] Re: Subselects open issue Nr. 5
Date
Msg-id 34E82975.1A267E8A@sable.krasnoyarsk.su
Whole thread Raw
In response to RE: [HACKERS] Re: Subselects open issue Nr. 5  ("Meskes, Michael" <meskes@topsystem.de>)
List 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

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