Michael,

> > is it possible to use an index on the expression '(table_1.field &
> > table_2.field)::int > 0' ?

Not practically, no.  

If it's important to you for comparisons to be indexed, then stop doing 
bitwise stuff and normalize your tables.   Bitwise fields are what is known 
as "non-atomic" data, and violate the First Normal Form (or is it the Second?  
Don't recall).   Your particular problem is one of the illustrations of why 
they are problematic.

The only times I use bitwise fields in my systems is when:
a) their content is going to be processed entirely by external (middleware/
interface) code and not queries, and
b) they will never themselves be a search condition.

-- 
-Josh Berkus
 Aglio Database Solutions
 San Francisco


Fri, 9 Apr 2004 20:15:59 -0700
Josh Berkus <josh@agliodbs.com>
Re: [DEFAULT] Daily digest v1.4379 (25 messages)