From: | Darko Prenosil <darko(dot)prenosil(at)finteh(dot)hr> |
---|---|
To: | shridhar_daithankar(at)persistent(dot)co(dot)in, zhangyue <postgresql(at)db(dot)pku(dot)edu(dot)cn> |
Cc: | pgsql-general(at)postgresql(dot)org |
Subject: | Re: [HACKERS] about NULL |
Date: | 2003-05-21 18:08:29 |
Message-ID: | 200305212008.29122.darko.prenosil@finteh.hr |
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Thread: | |
Lists: | pgsql-general pgsql-hackers |
On Wednesday 21 May 2003 10:46, Shridhar Daithankar wrote:
> On 21 May 2003 at 16:10, zhangyue wrote:
> > Hi,
> > How can I get the tuples one of whose attributes is NULL?
> > For example,
> > First, create table tb(id int,name text);
> > Then insert into tb values(1);
> > insert into tb values(2,'Rose');
> > I want to select the tuples whose attribute name= NULL,
> > How to write the sql ?
>
> select columns from table where attribute is null;
>
> This should have been on postgresql-general, not on hackers..
>
SELECT * FROM tb WHERE name IS NULL;
or even
SELECT * FROM tb WHERE name=NULL;
but the second one would work only if "transform_null_equals" is set to true
in postgresql.conf
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