geometry_column –
The geometry values to generate the collection. Typically this is a column.
Returns
ST_MultiSurface Returns a multisurface that contains all of the geometries in a group.
Examples
Example 1 –
The following example returns a single value which combines all geometries of type ST_Surface from the SpatialShapes table into a single collection of type ST_MultiSurface. If the Shape column was of type ST_Surface then the TREAT function and WHERE clause would not be necessary.
SELECT ST_MultiSurface::ST_MultiSurfaceAggr( TREAT( Shape AS ST_Surface ) )
FROM SpatialShapes WHERE Shape IS OF( ST_Surface )