On 2024-03-24 16:28 +0100, Thiemo Kellner wrote:
> Am 24.03.2024 um 16:17 schrieb Tom Lane:
>
> > To do that, we'd have to remember that you'd said NULL, which we
> > don't: the word is just discarded as a noise clause. Considering
> > that this usage of NULL isn't even permitted by the SQL standard,
> > that seems like a bit too much work.
>
> "Considering that this usage of NULL isn't even permitted by the SQL
> standard" is in my opinion a strange argument.
I don't know if the SQL standard ever allowed the NULL "constraint", but
the 2003 revision (the oldest one that I've got) does not allow it:
From Part 2, 11.4 <column definition>:
<column constraint> ::=
NOT NULL
| <unique specification>
| <references specification>
| <check constraint definition>
Postgres only accepts it to be compatible with other RDBMS. [1]
[1] https://www.postgresql.org/docs/current/sql-createtable.html#SQL-CREATETABLE-PARMS-NULL
--
Erik