Re: WHERE =NULL malfunction in release 7.2

On Thu, 20 Jun 2002, Ingo Ciechowski wrote:

> Unfortunaly there's a (hopefully easy to fix) bug in release 7.2 and
> 7.2.1 that was not there in 7.1.3 and caused me to switch back today.

Nope. It's a bug fix.

> However - if you want to access a <timestamp>=NULL value, it is not found :-((
>
>
>
> i++=# select * from uri where freigegeben=NULL;
>   template_id | content_id | freigegeben | gueltig_von | gueltig_bis |
> queue_status | site_id | uri
> -------------+------------+-------------+-------------+-------------+--------------+---------+-----
> (0 rows)

Which is correct because NULL does not equal NULL.  Think of NULL as
an unknown value, you don't know if two NULLs are equal.

In 7.1, there was a parser hack to allow this due to some older clients
that expected it to work.  In 7.2, you can turn this on with a variable
(TRANSFORM_NULL_EQUALS), however this behavior is contrary to the
SQL spec.