Date: Fri, 28 Feb 2014 08:33:09 -0800 (PST)
From: David Johnston <polobo@yahoo.com>
To: pgsql-sql@postgresql.org
Message-ID: <1393605189189-5794066.post@n5.nabble.com>
In-Reply-To: <1083597622.602688.1393603940121.JavaMail.root@mobiletech.sk>
References: <1001132708.567696.1393510818245.JavaMail.root@mobiletech.sk>
 <1393513774376-5793882.post@n5.nabble.com>
 <976203811.595346.1393587926835.JavaMail.root@mobiletech.sk>
 <1393601978985-5794056.post@n5.nabble.com>
 <1083597622.602688.1393603940121.JavaMail.root@mobiletech.sk>
Subject: Re: how to effectively SELECT new "customers"
MIME-Version: 1.0
Content-Type: text/plain; charset=us-ascii
Content-Transfer-Encoding: 7bit
Precedence: bulk
Sender: pgsql-sql-owner@postgresql.org

Jan Ostrochovsky wrote
> customer may have various payment channels during the time... new-ness is
> not impacted by the channel, it does not matter from which channel, all
> customer_id occurences count (in determined filtration criteria, e.g.
> town, service, subservice) 
> 
> and there are also other filtration and grouping criteria (town, service,
> subservice) and user of reporting tool should have possibility to select
> from those... there are dozens of services and subservices, cca 4 payment
> channels, dozens of towns... therefore preprocessing through materialized
> view (if I understand your suggestion correctly), would contain a lot of
> combinations, it seems quite complex for me in these circumstances 
> 
> I also considered WITH (CTEs) previously, I will rethink it yet, after
> these your recommendations 

I'm not sure what you are going for since you keep adding additional
criteria/constraints to your problem.  At this point you are faced with a
series of trade-offs between caching, speed, and flexibilty, complexity.  I
would suggest you break up your requirements into smaller pieces and not go
looking for some kind of magic bullet that will solve all your problems in a
single query.  It likely does not exist.

I would also suggest that you look into resources on data warehousing and
the star schema; doing what you are trying directly within the OLTP is
probably not the best solution - especially not on front-end servers.  My
experience in this area is thin but maybe someone else can make some
suggestions and/or provide some useful resource links.

David J.


--
View this message in context: http://postgresql.1045698.n5.nabble.com/how-to-effectively-SELECT-new-customers-tp5793867p5794066.html
Sent from the PostgreSQL - sql mailing list archive at Nabble.com.


-- 
Sent via pgsql-sql mailing list (pgsql-sql@postgresql.org)
To make changes to your subscription:
http://www.postgresql.org/mailpref/pgsql-sql