SELECT NEW ST_MultiCurve( 
	    NEW ST_LineString('LineString (0 0, 1 0)' ), 
	    NEW ST_CircularString( 'CircularString( 0 0, 1 1, 2 0)' ) )
	.ST_Length()

begin
    declare @multi_curve ST_MultiCurve;
    CREATE SPATIAL UNIT OF MEASURE IF NOT EXISTS  "example_unit_halfmetre" TYPE LINEAR CONVERT USING .5;
    set @multi_curve = NEW ST_MultiCurve( 
	    NEW ST_LineString('LineString (0 0, 1 0)' ), 
	    NEW ST_LineString('LineString (0 2, 2 2)' ) );
    SELECT @multi_curve.ST_Length('example_unit_halfmetre');
end