Subject RE: [firebird-support] Why NULL <> NULL ?
Author Dimitry Sibiryakov
On 19 May 2006 at 16:47, Alan McDonald wrote:

>equality of 2 unknown values. But if the "state" of 2 things is NULL,
>then I argue they should be equal in the same way that the last
>character on the end of all my C strings are the same!

That's why FB2 has introduced operation IS [NOT] DISTINCT FROM.

SY, Dimitry Sibiryakov.