From: Gary Stainburn <gary.stainburn@ringways.co.uk>
Organization: Ringways Garages Ltd
To: pgsql-sql@postgresql.org
Subject: Re: left outer join only select newest record
Date: Wed, 23 May 2012 10:47:27 +0100
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Appologies for not making it clearer. stock_details is simply a view of table 
stock, pulling in some lookup values.  used_diary is the name of the table 
containing the tax requests. It's called the used_diary because it was the 
diary for taxing used vehicles.

Here is a select to show the problem. There is one stock record and two tax 
records. What I'm looking for is how I can return only the second tax record, 
the one with the highest ud_id

select s_stock_no, s_regno, s_vin, s_created, ud_id, ud_handover_date from 
stock s left outer join used_diary u on s.s_regno = u.ud_pex_registration 
where s_stock_no = 'UL15470';

 s_stock_no | s_regno |       s_vin       |         s_created          | 
ud_id | ud_handover_date 
------------+---------+-------------------+----------------------------+-------+------------------
 UL15470    | YG12*** | KNADN312LC6****** | 2012-05-21 09:15:31.569471 | 
41892 | 2012-04-06
 UL15470    | YG12*** | KNADN312LC6****** | 2012-05-21 09:15:31.569471 | 
42363 | 2012-05-16
(2 rows)


On Wednesday 23 May 2012 10:37:31 Oliveiros d'Azevedo Cristina wrote:
> Gary,
>
> You describe two tables vehicle stock and tax requests. The former has a
> one-to-many relationship wit the second one, right?
>
> But your query involves stock details and used_diary.
>
> What is the relationship of these two new tables to the previous ones?
>
> Could you please kindly supply an example of what you have and of the
> desired output? For me it would be easier...
>
> Best,
> Oliver
>
> ----- Original Message -----
> From: "Gary Stainburn" <gary.stainburn@ringways.co.uk>
> To: <pgsql-sql@postgresql.org>
> Sent: Wednesday, May 23, 2012 10:27 AM
> Subject: [SQL] left outer join only select newest record
>
> > Hi folks,
> >
> > I know I've seen posts like this before but Google isn't helping today.
> >
> > I have two tables, vehicle stock and tax requests. Each vehicle can be
> > taxed
> > more than once, but I only want to pull in the most recent tax request -
> > the
> > one with the highest ud_id.
> >
> > I have the following, which obviously returning multiple records which
> > then
> > appears that the same vehicle is in stock multiple times.  How can I make
> > it
> > so we only show each vehicle once, showing the most recent tax request
> > details.
> >
> >
> > select * from stock_details s
> > left outer join used_diary u on s.s_registration = u.ud_registration;
> >
> >
> > --
> > Gary Stainburn
> > Group I.T. Manager
> > Ringways Garages
> > http://www.ringways.co.uk
> >
> > --
> > Sent via pgsql-sql mailing list (pgsql-sql@postgresql.org)
> > To make changes to your subscription:
> > http://www.postgresql.org/mailpref/pgsql-sql


-- 
Gary Stainburn
Group I.T. Manager
Ringways Garages
http://www.ringways.co.uk