In response to Louis-David Mitterrand :
> Hi,
> 
> I have a simple table 
> 
> price(id_product, price, date) 
> 
> which records price changes for each id_product. Each time a price
> changes a new tuple is created.
> 
> What is the best way to select only the latest price of each id_product?

There are several ways to do that, for instance with DISTINCT ON (only
postgresql):

test=*# select * from price ;
 id_product | price |   datum
------------+-------+------------
          1 |    10 | 2009-09-01
          1 |    12 | 2009-09-10
          2 |    11 | 2009-09-10
          2 |     8 | 2009-09-13
(4 rows)

test=*# select distinct on (id_product) id_product, price from price order by 
id_product, datum desc;
 id_product | price
------------+-------
          1 |    12
          2 |     8
(2 rows)

Andreas
-- 
Andreas Kretschmer
Kontakt:  Heynitz: 035242/47150,   D1: 0160/7141639 (mehr: -> Header)

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