Re: NOT IN performance problem

Maybe you can get faster results with minus: select distinct personid from persons
minus
select distinct personid from phones

Yechiel Adar
Mehish
----- Original Message -----
To: Multiple recipients of list ORACLE-L <ORACLE-L_at_fatcity.com> Sent: Tuesday, June 25, 2002 3:08 PM

>
>
> Hello,
>
> I have encountered a performance problem. I use "Oracle8 Enterprise
Edition
> Release 8.0.5.0.0 - Production."
>
> I have two tables. "phonenumber" and "person", each person has none, one
or
> many phonenumbers referenced to him.
>
> The phonenumber-table is structured like:
> phonenumber.personid
> phonenumber.phonenumber
>
> The person-table is structured like:
> person.personid
> person.name
> person.address
>
>
> I wan't to know which persons that does NOT have any phonenumber(s).
>
> I can write the query as:
> SELECT personid FROM phonenumber WHERE personid NOT IN (
> SELECT personid FROM person);
>
> However, since my tables are quite large, it takes forever to run my
query.
> In the real database both (or
> atleast one) of "person" or "phonenumber" are views.
>
> To figure out who _does_ have phonenumbers is SIGNIFICANTLY faster.
> (SELECT DISTINCT person.personid FROM person, phonenumber WHERE
> person.personid=phonenumber.personid)
>
> I'm wondering how I could restructure or rewrite my query ("who doesn't
have
> any phoinenumbers?") to run faster,
> or if there is anything else I can do to optimize the query?
>
> Any suggestions?
>
>
> --
> /Nils Höglund, Naqua KB
>
> E-mail: nils_at_naqua.se
> Web: http://www.naqua.se/
> Home Phone: +46 (0)18 30 09 19
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> INET: nils_at_naqua.se
>
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-- 
Please see the official ORACLE-L FAQ: http://www.orafaq.com
-- 
Author: Yechiel Adar
  INET: adar76_at_inter.net.il

Fat City Network Services    -- (858) 538-5051  FAX: (858) 538-5051
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