By using this site, you agree to our updated Privacy Policy and our Terms of Use. Manage your Cookies Settings.
437,541 Members | 1,525 Online
Bytes IT Community
+ Ask a Question
Need help? Post your question and get tips & solutions from a community of 437,541 IT Pros & Developers. It's quick & easy.

Sorting, when values are equal....

P: n/a
Hello,
If I do something like:

SELECT * FROM sometable ORDER BY somerow DESC LIMIT 1 OFFSET 2;

... and there are multiple rows in sometable where somerow is identical,
am I assured that the values will always come back in the same order?
...... Or do I need to ensure that a second sort (such as the oid?) is used?
Thanks!

- Greg


---------------------------(end of broadcast)---------------------------
TIP 9: the planner will ignore your desire to choose an index scan if your
joining column's datatypes do not match

Nov 23 '05 #1
Share this Question
Share on Google+
2 Replies


P: n/a
On Mon, Oct 25, 2004 at 04:45:15AM -0700, Net Virtual Mailing Lists wrote:
Hello,


If I do something like:

SELECT * FROM sometable ORDER BY somerow DESC LIMIT 1 OFFSET 2;

.. and there are multiple rows in sometable where somerow is identical,
am I assured that the values will always come back in the same order?
..... Or do I need to ensure that a second sort (such as the oid?) is used?
No order in guarenteed or implied unless you specify it. So you'll need
another field to order by, generally the primary key works well..
--
Martijn van Oosterhout <kl*****@svana.org> http://svana.org/kleptog/ Patent. n. Genius is 5% inspiration and 95% perspiration. A patent is a
tool for doing 5% of the work and then sitting around waiting for someone
else to do the other 95% so you can sue them.


-----BEGIN PGP SIGNATURE-----
Version: GnuPG v1.0.6 (GNU/Linux)
Comment: For info see http://www.gnupg.org

iD8DBQFBfPW0Y5Twig3Ge+YRAtLUAKC+RrJCjizFMfkXyukavx 70P2M7BgCgkkOU
k+c0jm58qCot0J+mzQV6gmo=
=c8vS
-----END PGP SIGNATURE-----

Nov 23 '05 #2

P: n/a
Net Virtual Mailing Lists wrote:
If I do something like:

SELECT * FROM sometable ORDER BY somerow DESC LIMIT 1 OFFSET 2;

.. and there are multiple rows in sometable where somerow is
identical, am I assured that the values will always come back in the
same order? .....
No.
Or do I need to ensure that a second sort (such as
the oid?) is used?


Yes.

--
Peter Eisentraut
http://developer.postgresql.org/~petere/
---------------------------(end of broadcast)---------------------------
TIP 7: don't forget to increase your free space map settings

Nov 23 '05 #3

This discussion thread is closed

Replies have been disabled for this discussion.