On Tuesday 06 April 2004 21:25, Ken Geis wrote:
> I am trying to find an efficient way to draw a random sample from a
> complex query. I also want it to be easy to use within my application.
>
> So I've defined a view that encapsulates the query. The id in the
> "driving" table is exposed, and I run a query like:
>
> select * from stats_record_view
> where id in (select id from driver_stats
> order by random()
> limit 30000);
How about a join?
SELECT s.*
FROM
stats_record_view s
JOIN
(SELECT id FROM driver_stats ORDER BY random() LIMIT 30000) AS r
ON s.id = r.id;
Or, what about a cursor and fetch forward (or back?) a random number of rows
before each fetch. That's probably not going to be so random though.
Also worth checking the various list archives - this has come up in the past,
but some time ago.
--
Richard Huxton
Archonet Ltd
