On Thu, 2008-07-24 at 14:49 +0200, 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
>
>
>
Run EXPLAIN for the statement on both systems and examine the results.
--
Just my 0.00000002 million dollars worth,
Shawn
"Where there's duct tape, there's hope."
"Perl is the duct tape of the Internet."
Hassan Schroeder, Sun's first webmaster
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