Dear Murad,
> I know you can emulate an 'exists' subquery with a join. but I just
> can't think of a way to emulate a 'not exists' without a subquery.
> probably due to my limited sql experience. any hints?
You have probably tried something like SELECT ... WHERE <condition> IS NOT
NULL. To emulate a "not exists" subselect, you would use SELECT ... WHERE
<condition> IS NULL.
> BTW: when do you think mysql 4.1 would be stable enough for robust use
As I hear, MySQL 4.1-alpha will be released very soon, probably in January.
My guess for MySQL 4.1-gamma (the release declared as stable, meaning there
are lots of installations in production environments that have proven
stable) is August 2003. Any other guesses? Monty? ;-)
Regards,
--
Stefan Hinz <hinz@stripped>
CEO / Geschäftsleitung iConnect GmbH <http://iConnect.de>
Heesestr. 6, 12169 Berlin (Germany)
Telefon: +49 30 7970948-0 Fax: +49 30 7970948-3
----- Original Message -----
From: "Murad Nayal" <mn216@stripped>
To: "MySQL List" <mysql@stripped>
Sent: Monday, December 09, 2002 4:37 PM
Subject: help on NOT EXISTS SQL query
>
>
> Hello all,
>
> I need to run query like (in mysql < ver.4):
>
> select * from table1 as t1 where not exists (select NULL from table2 as
> t2 where t1.field1 = t2.field1)
>
> I know you can emulate an 'exists' subquery with a join. but I just
> can't think of a way to emulate a 'not exists' without a subquery.
> probably due to my limited sql experience. any hints?
>
> thanks a lot
> Murad
>
> BTW: when do you think mysql 4.1 would be stable enough for robust use
> (not necessarily mission critical).
>
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