[postgis-users] merge geometries

[Chris Faulkner]

Hello

Is there any way to merge geometries using one of the functions in postgis.
If I have a table with 2 fields, ID and GEOMETRY. I have a list of ids and
would like to combine all the geometries in those ids.

select combine(GEOMETRY) from table where id in (1,2,3);

I expect that the function would return a type of MULTILINE, MULTIPOLYGON
and so on.

I can see a function geometry_union but this expects two parameters, two
geometries. My requirement is slightly different, or is there anyway of
using this to achieve what I want ?

Thanks


Chris