Re: Simple SQL Question

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От Bricklen
Тема Re: Simple SQL Question
Дата
Msg-id exOid.82125$df2.43102@edtnps89
обсуждение исходный текст
Ответ на Simple SQL Question  (Andras Kutrovics <n-drew@freemail.hu>)
Список pgsql-sql
Andras Kutrovics wrote:
> 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
> 
> that should be enough for an 'Item' table, but I have another
> column in the primary key.
> 
> let say, I have the following in Table1:
> 
> itemkey        location
> ------------------------
> 00001        00001
> 00001        00002
> ...
> 00005        00001
> 00005        00002
> 00005        00003 <--- lets say this is the last value
> 
> next time i want to run a query, which starts from
> 
> 00005        00004
> 00006        00005
> 
> and so on..
> 
> How can I specify that in sql?
> I dont want to use cursor:), I would like to do it in plain sql.
> (It it is possible).
> 
> Thank you in advance
> 
> Andras Kutrovics

maybe the OFFSET keyword will help here?


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