If I understand correctly, why don't you just ST_Union as you are doing below, then wrap the results in ST_Dump to
explode the MULTI result. Then you'll have your merged polygon where they overlap as well as any individual lone-ranger
polygons.
SELECT (ST_Dump(singlegeom)).geom
FROM (
SELECT ST_Multi(ST_Union(f.the_geom)) as singlegeom
FROM mytable
) AS foo;
-- Kevin
Alexandre Dube wrote:
Thanks for the help.
OK, using ST_Intersects should be fine when using only 2 geometries, but
how can I use this in a query on a table containing more than 15000 rows ?
ST_Union worked and returned a single multipolygon, that's a good
start. Is it possible to merge "intersecting" polygons only in a
statement ?
So far :
SELECT mycolumn, ST_Multi(ST_Union(f.the_geom)) as singlegeom FROM
mytable As f GROUP BY mycolumn;
(btw, mycolumn has the same value for every row, i.e. is null)
Thanks a lot,
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