Re: Simple SQL Question

Franco Bruno Borghesi wrote:

Hi!

Sorry for being late with the answer, I was busy at one of our customer;)

> wouldn't it be easier using offset & limit?: you always select from the
> table with an itemkey,location order by clause. You save the current
> offset between requests, and for every request you re-execute the query
> with a different offset.
Sure, but sometimes I have to query by name, and dont want to create
another query component.

> If you still want to go with what you already have, you should keep the
> lastItemKey and lastLocaltion values between requests, and your where
> clause should be something like:
> WHERE (itemKey=:lastItemKey AND location>:lastLocation) OR
> (itemKey>:lastItemKey)

It works perfectly, but I have to consider the performance issue,
because if i use 'or' statement, postgres doesn't use index scan,
and I also have tables with 3 or more keys and 500.000 records ,
where
the performance of this method is poor.
Maybe I will end up using limit and offset in case of incremental
fetching,but if the table is modified between requests, it can behave
weird.
Is there a perfect solution to this?

Sorry for the english

Thank you again,

Andras Kutrovics