Error when creating new view using ST_Union (PostGIS)

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I have a table in PostGIS (2.1.7) containing adjacent multipolygons, and I'd like to create a view containing polygons which are merged versions of the multipolygons based on some field value.

I tried the following query:

CREATE VIEW results ASSELECT somefield, ST_Union(geom)::geometry(Polygon, 2056) AS geom FROM somelayer GROUP BY somefield;and I got the following error:

Geometry type (MultiPolygon) does not match column type (Polygon)

​

I thus tried to change the result type to multipolygon:

CREATE VIEW results AS SELECT somefield, ST_Union(geom)::geometry(MultiPolygon, 2056) AS geom FROM somelayer GROUP BY somefield;But it didn't help since I got the following error:

Geometry type (Polygon) does not match column type (MultiPolygon)

​

The following query finally worked but it is not optimal since I'd like to have polygons instead of multipolygons (it should be possible since the resulting polygons are all singlepart):

CREATE VIEW results AS SELECT somefield, ST_Multi(ST_Union(geom))::geometry(MultiPolygon, 2056) AS geom FROM somelayer GROUP BY somefield;How can I get the desired results? Thanks a lot!



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