Re: Constraint on multicolumn index

"Stuart Brooks" <stuartb(at)cat(dot)co(dot)za> writes:
> But if I want the next item following t=(a=10,b=100,c=1000):

> select * from T
> where (a=10 AND b=100 AND c>1000) OR (a=10 AND b>100) OR (a>10)
> order by a,b,c;

The correct way to handle this is to use a SQL-spec row comparison:

where (a,b,c) > (10,100,1000)

Unfortunately, that syntax does not work per-spec in any existing
Postgres release. It will work properly (and use the index) in
PG 8.2, for what that's worth.

Not sure if there's any reasonable workaround in PG <= 8.1.
You might want to check this old thread:
http://archives.postgresql.org/pgsql-performance/2004-07/msg00188.php
(note that none of the first few responses got the point :-() Also
http://archives.postgresql.org/pgsql-hackers/2006-02/msg00209.php

regards, tom lane