Re: tricky query

John A Meinel schrieb:

> John A Meinel wrote:
>
>>
>
> Well, I was able to improve it to using appropriate index scans.
> Here is the query:
>
> SELECT t1.id+1 as id_new FROM id_test t1
> WHERE NOT EXISTS
> (SELECT t2.id FROM id_test t2 WHERE t2.id = t1.id+1)
> ORDER BY t1.id LIMIT 1;
>
> I created a test table which has 90k randomly inserted rows. And this is
> what EXPLAIN ANALYZE says:
>
>

As Cosimo stated the result can be wrong. The result is always wrong
when the id with value 1 does not exist.

--
Best Regards / Viele Grüße

Sebastian Hennebrueder

----

http://www.laliluna.de

Tutorials for JSP, JavaServer Faces, Struts, Hibernate and EJB

Get support, education and consulting for these technologies - uncomplicated and cheap.