Re: Avoid a subselect "where not equal to"?

Martin T. wrote:
> andrew.fabbro_at_gmail.com wrote:
> > (snipped)
> >
> > And that worked fine. However, someone else referred to this as a
> > "nasty" query, opining that "where not in (select...) queries are some
> > of the worst" in a performance sense.
> >
>
> But ... thats exactly what you want to know, isn't it?
> -> "Give me all new ones where no open ones exist."
> So I guess it's OK to ask Oracle exactly that :)
>
> I think this query can scale very well, with the right indexes ...
>
> best,
> Martin

Indices alone won't help. Charles Hooper gave a good solution. An outer join where you pick the rows with NULL works. But it all depends on the version of ORACLE.

 Ed Received on Tue Aug 01 2006 - 14:21:54 CDT