I have a json element with this structure

obj_type
-_1,

    -start
    - end    
-_2,
   -start
   -end    
-_3,
  -start
  -end

I would like to obtain a table like this

| obj_type | 1_start| 1_end | 2_start | 2_end | 3_start | 3_end |

| _1 |

| _2 | ………………………………… value………….

| _3 |

WITH d (department_data) AS (SELECT (UTL_RAW.cast_to_raw ('{
  "r": [
    {
      "obj_type": "A",
      "_1":  {
        "start": "1",
        "end": "2"
        },
        "_2":  {
        "start": "15",
        "end": "25"
        },
        "_3":  {
        "start": "26",
        "end": "33"
        }
    },
    {
      "obj_type": "B",
      "_1": {
        "start": "1",
        "end": "2"
    },
        "_2":  {
        "start": "3",
        "end": "12"
        }
    },    {
      "obj_type": "C",
      "_2":{
        "start": "1",
        "end": "2"
    }
    },    {
      "obj_type": "D",
      "_3": {
        "start": "",
        "end": "2"
    }
    }
  ]
}')) FROM DUAL)
--select * from d;
SELECT j.*
  FROM d,
       JSON_TABLE (
           d.department_data,
           '$'
           COLUMNS (

               NESTED PATH '$.r[*]'
                    COLUMNS (
                        name PATH '$.obj_type', 
                        NESTED PATH '$._1[*]'
                            columns ("_1_start" PATH '$.start',
                                     "_2_end" PATH '$.end'),
                        NESTED PATH '$."_2"[*]'
                            columns ("UVG_start" PATH '$.start',
                                     "UVG - Zusatz_end" PATH '$.end'),
                        NESTED PATH '$."_3"[*]'
                            columns ("UVG - Ueberschusslohn_start" PATH '$.start',
                                     "UVG - Ueberschusslohn_end" PATH '$.end')
                            ))) j

This query is not returning what I’ve expected.

The lines are duplicated. start and end from _1 are not the same line of start and end from _2.
Furthermore if there is no value they are not printed.

code