From: | "John Lister" <john(dot)lister-ps(at)kickstone(dot)com> |
---|---|
To: | <pgsql-sql(at)postgresql(dot)org> |
Subject: | obtaining difference between minimum value and next in size |
Date: | 2010-11-17 15:11:32 |
Message-ID: | 3BC753A3784F488F98304300B6E437FD@squarepi.com |
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Thread: | |
Lists: | pgsql-sql |
Hi, I was wondering if it is possible to do this with a single query rather than iterate over all of the rows in an application:
I have a table which for brevity looks like:
create table offers {
integer id;
integer product_id;
double price;
}
where for each product there is a number of offers in this table. Now my question:
Is it possible to obtain the difference between just the minimum price and the next one up per product, so say I have the following data:
id, product_id, price
123, 2, 10.01
125, 2, 10.05
128, 2, 11.30
134, 3, 9.45
147, 3, 11.42
157, 3, 12.08
167, 3, 12.09
then I would like the following returned
product_id, difference
2, .04 (10.05-10.01)
3, 1.97 (11.42-9.45)
,etc
Any ideas?
Thanks
John
--
Got needs? Get Goblin'! - http://www.pricegoblin.co.uk/
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