>to get the latest value for each id i have queries like:
>select * from tab A where timestamp = (select max(timestamp) from tab B where
> B.id=A.id) group by id ;
See "Within-group aggregates" at
http://www.artfulsoftware.com/infotree/queries.php.
PB
walter harms wrote:
> hi list,
> i have tables that look like this( <10.000 entries) :
>
> id,
> timestamp,
> value
>
>
> to get the latest value for each id i have queries like:
>
> select * from tab A where timestamp = (select max(timestamp) from tab B where
> B.id=A.id) group by id ;
>
> on a fast system it takes round 4 sec to complet, but since this is done requlary it
> slows down to much.
> the same query takes on a informix system an a slower computer next to nothing.
>
> any ideas ?
>
> re,
> walter
>
>
>
>
