Re: How to select rows with values set to NULL

On Thu, 23 May 2002, Tille, Andreas wrote:

Seems to work here:

jaa=# create table test2(id int, txt varchar(17) default NULL);
CREATE

jaa=# insert into  test2 values(1);
INSERT 420453 1

jaa=# select * from test2 where txt = null;
 id | txt
----+-----
  1 |
(1 row)

psql (PostgreSQL) 7.1.2


BR, Jani

>
> Hello,
>
> InfluenzaWeb=# create table test (
> InfluenzaWeb(#   id int,
> InfluenzaWeb(#   txt varchar(17) default NULL);
> CREATE
> InfluenzaWeb=# insert into test values( 1 );
> INSERT 553756 1
> InfluenzaWeb=# select * from test;
>  id | txt
> ----+-----
>   1 |
> (1 row)
>
> InfluenzaWeb=# select * from test where txt = NULL;
>  id | txt
> ----+-----
> (0 rows)
>
> InfluenzaWeb=#  insert into test values(2,'text');
> INSERT 553757 1
> InfluenzaWeb=# select * from test where txt like '%';
>  id | txt
> ----+------
>   2 | text
> (1 row)
>
> InfluenzaWeb=# select * from test where not txt like '%';
>  id | txt
> ----+-----
> (0 rows)
>
> So how to get all rows which txt has the value NULL?
>
> Kind regards
>
>          Andreas.
>
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--
Jani Averbach