From: Alain Reymond <arwebmail@skynet.be>
To: pgsql-sql@postgresql.org
Subject: How do write a query...
Date: Wed, 01 Jun 2005 18:00:49 +0200
Message-ID: <429DDBB1.7000204@skynet.be> (raw)
Hello,
I have the following problem :
I have a table like
Id Num Date AValue
1 10 01/01/2005 50
2 10 31/05/2005 60
3 25 02/02/2005 55
4 25 15/03/2005 43
5 25 28/05/2005 62
etc..
Id is unique, Num is an identification number with duplicates possible,
date is a ... date and Avalue... a value!
If we have
Id Num Date AValue
Id1 Num1 Date1 AValue1
Id2 Num1 Date2 AValue2
The table is ordered on Num+Date.
What I would like to calculate is (AValue2-AValue1) for a given Num
(here num1).
In this case, I would have to calculate
60-50 for Num 10
and
43-55, 62-43 for Num 25.
Do you have any idea if it can be done simply with a request...
I thank you
Regards.
Alain Reymond
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Subject: Re: How do write a query...
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