about NULL

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..

HTH

Bye
Shridhar

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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 * FROM tb WHERE name IS NULL;

Chris

SELECT * FROM tb WHERE name IS NULL;

And I think it should have been on the SQL list, myself...

Shridhar Daithankar wrote:

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