ST_CollectionHomogenize-PolarDB(PolarDB)-阿里云帮助中心

Returns the simplest geometry representation of a GeometryCollection.

Syntax

geometry ST_CollectionHomogenize(geometry collection);

Parameter	Description
collection	The input `GeometryCollection`.

If the collection contains a collection of singleton objects, the function returns a singleton object.
If the collection contains multiple geometries of the same type, the function returns the equivalent MULTI geometry type.

SELECT ST_AsText(ST_CollectionHomogenize(ST_GeomFromText('GEOMETRYCOLLECTION(LINESTRING(1 1,2 1),LINESTRING(2 1,2 2))')));

Output:

              st_astext
--------------------------------------
 MULTILINESTRING((1 1,2 1),(2 1,2 2))
(1 row)