Message-ID: <418BC1F3.7080205@klaster.net>
Date: Fri, 05 Nov 2004 19:09:55 +0100
From: Tomasz Myrta <jasiek@klaster.net>
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To: Andras Kutrovics <n-drew@freemail.hu>
Cc: pgsql-sql@postgresql.org
Subject: Re: Simple SQL Question
References: <418BB051.6070808@freemail.hu>
In-Reply-To: <418BB051.6070808@freemail.hu>
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> Hi All!
> 
> In one of my application, I would like to implement incremental
> fetching. The problem is that I would like to run it
> from a stateless application server, so I have to tell where
> to begin fetching data. It is simple for a table which has single column
> primary key, but causes difficulties (at least for me) in
> a more-column primary key..
> 
> Let say I have a table wich has the primary key: itemkey,location
> 
> table1
> ------
> itemkey
> location
> ...
> --------
> 
> 
> select * from table1 LIMIT x
> 
> gives me the first x row of the result.
> After that, I save the last value, and next time, I adjust
> the query as
> 
> select * from table1 where itemkey>:lastvalue LIMIT x

Why do you complicate it so much? Everything you need is:

select * from table1 LIMIT x
select * from table1 LIMIT x OFFSET x
select * from table1 LIMIT x OFFSET 2*x

Remember to sort rows before using limit/offset.

Regards,
Tomasz Myrta