El Sáb 13 Dic 2003 16:21, MT escribió:
> Hi,
>
> I have an invoicing system using postgresql. Each time a customer makes a
purchase, a new record is inserted into the "cart" table. The "cart" table,
among other things, contains a customer_id field and a total for the amount
purchased on the particular invoice. Now what I'd like to do is to calculate
the total invoices for each customer in a given time interval, then list
those customers in descending order from most paying to least paying. Could
someone give me some pointers on how to construct an sql statement that would
flush out this data.
First, lets see how to get the info you want:
SELECT sum(invoice) AS total, customer_id FROM cart
GROUP BY cuotomer_id;
Now you can order it by the total column, and maybe give it a LIMIT, in case
you have to many costumers. :-)
--
select 'mmarques' || '@' || 'unl.edu.ar' AS email;
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Martín Marqués | mmarques@unl.edu.ar
Programador, Administrador, DBA | Centro de Telemática
Universidad Nacional
del Litoral
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