Re: WHERE clause OR vs IN

-----BEGIN PGP SIGNED MESSAGE-----
Hash: SHA1

On Wed, 12 Dec 2007 14:25:16 -0800
"Medi Montaseri" <montaseri(at)gmail(dot)com> wrote:

> Hi,
>
> I know this is not exactly admin related, but ... it is simple enough
> to be even fun
>
> From a performance point of view, is it better to use OR as in
> SELECT expr FROM expr WHERE col=this OR col=that OR col=theOther
> Or to use a range of values as in
> SELECT expr FROM expr WHERE col in ( val1, val2, ...., valn)
>
> I think the IN range yields a better query plan .... what do you
> think ? Thanks

Well a simple test:

postgres=# explain analyze select * from tellers where bid in ('1','2');
QUERY
PLAN
- ------------------------------------------------------------------------------------------------------
Seq Scan on tellers (cost=0.00..10.25 rows=20 width=352) (actual
time=0.019..0.192 rows=20 loops=1) Filter: (bid = ANY
('{1,2}'::integer[])) Total runtime: 0.314 ms (3 rows)

postgres=# explain analyze select * from tellers where bid = '1' or bid
= '2'; QUERY PLAN
- ------------------------------------------------------------------------------------------------------
Seq Scan on tellers (cost=0.00..11.50 rows=20 width=352) (actual
time=0.018..0.199 rows=20 loops=1) Filter: ((bid = 1) OR (bid = 2))
Total runtime: 0.275 ms
(3 rows)

postgres=#

> Medi

- --
The PostgreSQL Company: Since 1997, http://www.commandprompt.com/
Sales/Support: +1.503.667.4564 24x7/Emergency: +1.800.492.2240
Donate to the PostgreSQL Project: http://www.postgresql.org/about/donate
SELECT 'Training', 'Consulting' FROM vendor WHERE name = 'CMD'

-----BEGIN PGP SIGNATURE-----
Version: GnuPG v1.4.6 (GNU/Linux)

iD8DBQFHYGJwATb/zqfZUUQRAs32AJ9HuJVcY5gcr0hboxkI6PcRtv++JwCfXd00
nQ7Frkof0mVwqNYVxQ9Vziw=
=XzJi
-----END PGP SIGNATURE-----