| Subject | Re: [Firebird-general] ... WHERE PARENT_ID = NULL |
|---|---|
| Author | Ann W. Harrison |
| Post date | 2004-07-08T16:15:19Z |
At 09:15 AM 7/8/2004, esrefatak wrote:
question to the support list and then answer it there, but I'm
impatient. The technical reason is that the SQL standard says
that the test for nullity is IS NULL. The logical reason is that
equality is transitive. If A = B and C = B then A = C. However
if A IS NULL and B IS NULL, A is not the same as B.
Regards,
Ann
>Why can not i use a statement like?:this is off topic on this list. I should request that you send the
>
>"SELECT NAME
>FROM EMPLOYEE
>WHERE PARENT_ID = NULL" ?
>
>What is the logical and technical explanation of this?
question to the support list and then answer it there, but I'm
impatient. The technical reason is that the SQL standard says
that the test for nullity is IS NULL. The logical reason is that
equality is transitive. If A = B and C = B then A = C. However
if A IS NULL and B IS NULL, A is not the same as B.
Regards,
Ann