Kevin Grittner wrote:
>>>> On Thu, Aug 23, 2007 at 3:01 PM, in message <11856.1187899268@sss.pgh.pa.us>,
> Tom Lane <tgl@sss.pgh.pa.us> wrote:
>> The only argument I've
>> heard that carries much weight with me is that it eases porting from
>> other DBMS's that allow this. Are there any others besides Oracle?
>
>> select * from (select f1 from t)
>
> In Sybase:
>
> com.sybase.jdbc2.jdbc.SybSQLException: The derived table expression is missing a correlation name. Check derived
tablesyntax in the Reference Manual.
> Error code: 11753
> SQL state: ZZZZZ
The really funny thing is that pgsql, mysql and at least sybase
*explicitly* dissallow the no-alias case. Which shows that .) This seems to be common source of confusion and errors.
.)Aliasless-Subqueries wouldn't lead to ambigous grammras in those databases. Otherwise, you'd expect to get some
moregeneric syntax error, and not the very explicit "No alias, but expected one".
I agree with Tom - knowing *why* the standard committee disallows that syntax -
and why everybody except oracle chose to agree with it would be quite interesting.
greetings, Florian Pflug