LRS SDO_GEOMETRY to "LINESTRING M" WKT format

Question

I have a query that produces an LRS SDO_GEOMETRY as WKT (Oracle 18c):

select  
    SDO_UTIL.TO_WKTGEOMETRY(SDO_LRS.CONVERT_TO_LRS_GEOM(sdo_geometry('LINESTRING(1 2,3 4)'))) 
from
    dual

Output:
LINESTRING (1.0 2.0 0.0, 3.0 4.0 2.82842712474619)
          ^

That output isn't quite the format that I need. I need the WKT to indicate that the third dimension is M-values, not imply that the third dimension is Y-values:

LINESTRING M (1.0 2.0 0.0, 3.0 4.0 2.82842712474619)
           ^

How can I output a LRS SDO_GEOMETRY using the LINESTRING M format?

(Or the MULTILINESTRING M format, if the geometry is multi-part.)

Answer 1

I suppose I could use the REPLACE() function to replace LINESTRING ( with LINESTRING M (:

select
    replace(sdo_geom,   'LINESTRING (',   'LINESTRING M ('   ) as wkt_m
from
    (
    select  
        SDO_UTIL.TO_WKTGEOMETRY(SDO_LRS.CONVERT_TO_LRS_GEOM(sdo_geometry('LINESTRING(1 2,3 4)'))) as sdo_geom
    from
        dual
    )

Output:
LINESTRING M (1.0 2.0 0.0, 3.0 4.0 2.82842712474619)
           ^

It seems to work for multi-part LRS geometries too:

select
    replace(sdo_geom,   'LINESTRING (',   'LINESTRING M ('   ) as wkt_m
from
    (
    select  
        SDO_UTIL.TO_WKTGEOMETRY(SDO_LRS.CONVERT_TO_LRS_GEOM(sdo_geometry('MULTILINESTRING ((1 2,3 4),(5 6,7 8))'))) as sdo_geom
    from
        dual
    )

MULTILINESTRING M ((1.0 2.0 0.0, 3.0 4.0 2.82842712474619), (5.0 6.0 2.82842712474619, 7.0 8.0 5.65685424949238))
^^^^^           ^