On 16 January 2013 20:23, Robert James <srobertjames(at)gmail(dot)com> wrote:
> Is there a recommended, high performance method to check for subdomains?
>
> Something like:
> - www.google.com is subdomain of google.com
> - ilikegoogle.com is not subdomain of google.com
>
> There are many ways to do this (lowercase and reverse the string,
> append a '.' if not there, append a '%', and do a LIKE). But I'm
> looking for one that will perform well when the master domain list is
> an indexed field in a table, and when the possible subdomain is either
> an individual value, or a field in a table for a join (potentially
> indexed).
>
Maybe the ltree extension will suit what you are trying to do?
http://www.postgresql.org/docs/9.2/static/ltree.html