DomainKey-Signature: a=rsa-sha1; c=nofws; d=gmail.com; s=gamma;
	h=mime-version:sender:in-reply-to:references:from:date
	:x-google-sender-auth:message-id:subject:to:cc:content-type
	:content-transfer-encoding;
	b=Mbg2g4FdnwAcd0Lxqzu0sxHxsN2Z9RcUPFIjZyx7Gb1UPb4zTkTDsIqxsce3vbkO7c
	WMpvkTa3C69vseP2x5NL7Fe0VweWdYQwo5s6lqhOneWc2qbjBHMgsfEJ22ji9mW88rYz
	qBeTKY0i+LxOnS2ReOKJrYQKWemnAhMparRHY=
MIME-Version: 1.0
In-Reply-To: <a0eee4d40907020748p7cb9bad7mad8817e60e9ea89@mail.gmail.com>
References: <a0eee4d40907020748p7cb9bad7mad8817e60e9ea89@mail.gmail.com>
From: Greg Stark <gsstark@mit.edu>
Date: Thu, 2 Jul 2009 22:21:01 +0100
Message-ID: <407d949e0907021421qb1df8b1o9468f343298f08dd@mail.gmail.com>
Subject: Re: Create custom aggregate function and custom sfunc
To: Jasmin Dizdarevic <jasmin.dizdarevic@gmail.com>
Cc: pgsql-sql@postgresql.org
Content-Type: text/plain; charset=ISO-8859-1
Content-Transfer-Encoding: quoted-printable

On Thu, Jul 2, 2009 at 3:48 PM, Jasmin
Dizdarevic<jasmin.dizdarevic@gmail.com> wrote:
> customer ; seg
> 111 ; L1
> 111 ; L2
> 111 ; L1
> 222 ; L3
> 222 ; L3
> 222 ; L2
>
> the result should look like this:
>
> 111: L1 - because L1 is higher than L2 and ratio of L1 : L2 is 2 : 1
> 222: L3 - because L3 is higher than L2 and ratio of L3 : L2 is=A02 : 1

Are you just looking for the most frequent seg for each customer?

select distinct on (customer) customer,seg
   from (select customer, seg, count(*) as n from tab group by seg)
  order by customer, n desc

That doesn't give the ratios though.

--=20
greg
http://mit.edu/~gsstark/resume.pdf