Message-ID: <597755AB8EE8458F92F4B7C6588E5C03@marktestcr.marktest.pt>
From: "Oliveiros" <oliveiros.cristina@marktest.pt>
To: "Wes James" <comptekki@gmail.com>,
	<pgsql-sql@postgresql.org>
References: <AANLkTik3O3L0PLqy4SN5oHy9zSBf8TDLXzGZcPYLtEXf@mail.gmail.com>
Subject: Re: how to construct sql
Date: Wed, 2 Jun 2010 17:55:18 +0100
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Hi,
Have you already tried this out?

select MAX(page_count_count) - MIN(page_count_count)  
from page_count 
group by page_count_pdate.


Best,
Oliveiros

----- Original Message ----- 
From: "Wes James" <comptekki@gmail.com>
To: <pgsql-sql@postgresql.org>
Sent: Wednesday, June 02, 2010 5:48 PM
Subject: [SQL] how to construct sql


>I am grabbing a printer total and putting it in a table.  The
> page_count is continuously increasing:
> 
> page_count_count        page_count_pdate
> 10                               2010-05-10
> 20                               2010-05-10
> 40                               2010-05-11
> 60                               2010-05-11
> 80                               2010-05-11
> 100                               2010-05-12
> 120                               2010-05-12
> .....
> 
> and so on.
> 
> I can do:
> 
> select sum(page_count_count) from page_count group by page_count_pdate.
> 
> and get a total for a day.  But this is not the total I want.  I want
> the total page count for the day.  This would mean getting the first
> page count of the day and then subtracting that from last page_count
> for the day.  For 2010-05-11 above it would be
> 
> 80 - 40 = 40 total for the day.  Is there a way to do this with sql?
> 
> thx,
> 
> -wes
> 
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