[postgis-users] Query with LIMIT but as random result set?

[Stefan Keller]

Hi,

Thanks a lot to Adrian, Nicolas and Brooks.
"... ORDER BY random() LIMIT 10;" works ok.

But with the following option it gets more tricky assume:
> And as an option the (limited) resultset should be spatially
> distributed (not clustered).

I'm thinking about some radial spatial distribution function.

Yours, Stefan


2013/1/8 Brooks Kehler <brookskehler at gmail.com>:
> this should work -
>
> order by random() limit 10;
>
>
>
> On Tue, Jan 8, 2013 at 10:20 AM, Stefan Keller <sfkeller at gmail.com> wrote:
>>
>> Hi
>>
>> I have a query like this
>>
>>   SELECT ST_AsText(way) geom, name AS label
>>   FROM osm_point
>>   LIMIT 10;
>>
>> When I repeatedly do this, the result set will be always the same.
>> I have observed this only empirically and I know that the ordering of
>> the result set is undefined without ORDER BY.
>> There are two indexes involved, one geospatial for way and one for name.
>>
>> My question is: Does someone have an idea on how to randomize the
>> result set on every consecutive query?
>> And as an option the (limited) resultset should be spatially
>> distributed (not clustered).
>>
>> Yours, Stefan
>> _______________________________________________
>> postgis-users mailing list
>> postgis-users at lists.osgeo.org
>> http://lists.osgeo.org/cgi-bin/mailman/listinfo/postgis-users
>
>
>
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