[AccessD] query to slow

  Hello Gustav and Chester,

thanks for the help.

I will try this tomorrow.

I'll hope will hope for large numbers of records.

But i still need the subquery for counting measures.
May be there is a work around for this counting.
If i don't manage it by myself, i will get back to the list for help.

Rocky, Patientnr is indexed.


Thanks

Pedro





Op 28-9-2010 17:28, Gustav Brock schreef:
> Hi Pedro
>
> Why not just:
>
> SELECT
>    Patientnr,
>    Max(UitvoerDatum) As UitvoerDatumLast
> FROM
>    qryKreatinine
> GROUP BY
>    Patientnr;
>
> /gustav
>
>
>>>> pedro at plex.nl 28-09-2010 17:04>>>
> Dear List,
>
> i have a query<qryKreatinine>  with about 400000 records.
> This query contains patientnumbers and dates
>
>
> <qryKreatinine>
> Patientnr   UitvoerDatum
> 01000616    1-6-2009
> 01000616    29-7-2009
> 01000661    1-5-2010
> 01000661    3-6-2010
> 01000661    3-6-2010
> 01000832    11-9-2009
> 01000832    17-9-2009
> 01000832    1-3-2010
>
> I need to have for each Patientnumber, the last date (see final result).
> I did this with two queries (see below), but only with low number queries (a few thousand records.
> With more then 500000 records it takes to much time to get the result.
>
> Can i do this with 1 query in a normal time span for 400000 records??
>
>
> Thanks
>
> Pedro
>
>
>