ST_GeomCollection If the geometry-expression is of type ST_GeomCollection, returns the geometry-expression. If the geometry-expression is of type ST_Point, ST_Curve, or ST_Surface, then return a geometry collection containing one element, the geometry-expression. If the geometry-expression is the empty set, returns an empty set of type ST_GeomCollection. Otherwise, raises an exception condition.
Examples
Example 1 –
The following example returns the result GeometryCollection (Point (0 1)).