Re: Simple SQL Question - Mailing list pgsql-sql

From Tomasz Myrta
Subject Re: Simple SQL Question
Date
Msg-id 418BC1F3.7080205@klaster.net
Whole thread Raw
In response to Simple SQL Question  (Andras Kutrovics <n-drew@freemail.hu>)
Responses Re: Simple SQL Question
List pgsql-sql
> 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



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