Date: Wed, 5 Mar 2008 09:33:53 -0800 (PST)
From: Jeff Frost <jeff@frostconsultingllc.com>
To: pgsql-sql@postgresql.org
Subject: finding columns that have three or fewer distinct characters
Message-ID: 
 <Pine.LNX.4.64.0803050912570.4804@discord.home.frostconsultingllc.com>
MIME-Version: 1.0
Content-Type: TEXT/PLAIN; charset=US-ASCII; format=flowed

I've got an interesting one...I'm trying to find columns that have three or 
fewer distinct characters (for example, "aaaaaaaaaa").  Wondering if I need to 
write a function or if someone has an idea how to do it with built in 
functions and/or pattern matching?

I think the thing to do would be to lowercase everything, then remove all 
duplicate chars and spaces, then use length() on that, but it's not obvious to 
me how I might remove the duplicate chars with the pattern matching support 
in the docs.

-- 
Jeff Frost, Owner 	<jeff@frostconsultingllc.com>
Frost Consulting, LLC 	http://www.frostconsultingllc.com/
Phone: 650-780-7908	FAX: 650-649-1954