Oracle 21c

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with t as ( 
        select 'A1'    CODE, 'JOB_1_1' CODE_NM, 'A'    PARENT_ID, NULL ETC1, NULL ETC2 from dual union all 
        select 'A2'    CODE, 'JOB_1_2' CODE_NM, 'A'    PARENT_ID, NULL ETC1, NULL ETC2 from dual union all 
        select 'A3'    CODE, 'JOB_1_3' CODE_NM, 'A'    PARENT_ID, NULL ETC1, NULL ETC2 from dual union all 
        select 'B01'   CODE, 'JOB_2_1' CODE_NM, 'A1'   PARENT_ID, NULL ETC1, NULL ETC2 from dual union all 
        select 'B02'   CODE, 'JOB_2_2' CODE_NM, 'A2'   PARENT_ID, NULL ETC1, NULL ETC2 from dual union all 
        select 'B03'   CODE, 'JOB_2_3' CODE_NM, 'A3'   PARENT_ID, NULL ETC1, NULL ETC2 from dual union all 
        select 'C001'  CODE, 'JOB_3_1' CODE_NM, 'B01'  PARENT_ID, NULL ETC1, NULL ETC2 from dual union all 
        select 'C002'  CODE, 'JOB_3_2' CODE_NM, 'B02'  PARENT_ID, NULL ETC1, NULL ETC2 from dual union all 
        select 'C003'  CODE, 'JOB_3_3' CODE_NM, 'B03'  PARENT_ID, NULL ETC1, NULL ETC2 from dual union all 
        select 'D0001' CODE, 'JOB_4_1' CODE_NM, 'C999' PARENT_ID, 'C001' ETC1, 'C003' ETC2 from dual union all 
        select 'D0002' CODE, 'JOB_4_2' CODE_NM, 'C999' PARENT_ID, 'C001' ETC1, 'C003' ETC2 from dual union all 
        select 'D0003' CODE, 'JOB_4_3' CODE_NM, 'C999' PARENT_ID, 'C001' ETC1, 'C003' ETC2 from dual 
    ) 
 select * from t


CODE
CODE_NM
PARENT_ID
ETC1
ETC2


A1
JOB_1_1
A
null
null

A2
JOB_1_2
A
null
null

A3
JOB_1_3
A
null
null

B01
JOB_2_1
A1
null
null

B02
JOB_2_2
A2
null
null

B03
JOB_2_3
A3
null
null

C001
JOB_3_1
B01
null
null

C002
JOB_3_2
B02
null
null

C003
JOB_3_3
B03
null
null

D0001
JOB_4_1
C999
C001
C003

D0002
JOB_4_2
C999
C001
C003

D0003
JOB_4_3
C999
C001
C003


with t as ( 
        select 'A1'    CODE, 'JOB_1_1' CODE_NM, 'A'    PARENT_ID, NULL ETC1, NULL ETC2 from dual union all 
        select 'A2'    CODE, 'JOB_1_2' CODE_NM, 'A'    PARENT_ID, NULL ETC1, NULL ETC2 from dual union all 
        select 'A3'    CODE, 'JOB_1_3' CODE_NM, 'A'    PARENT_ID, NULL ETC1, NULL ETC2 from dual union all 
        select 'B01'   CODE, 'JOB_2_1' CODE_NM, 'A1'   PARENT_ID, NULL ETC1, NULL ETC2 from dual union all 
        select 'B02'   CODE, 'JOB_2_2' CODE_NM, 'A2'   PARENT_ID, NULL ETC1, NULL ETC2 from dual union all 
        select 'B03'   CODE, 'JOB_2_3' CODE_NM, 'A3'   PARENT_ID, NULL ETC1, NULL ETC2 from dual union all 
        select 'C001'  CODE, 'JOB_3_1' CODE_NM, 'B01'  PARENT_ID, NULL ETC1, NULL ETC2 from dual union all 
        select 'C002'  CODE, 'JOB_3_2' CODE_NM, 'B02'  PARENT_ID, NULL ETC1, NULL ETC2 from dual union all 
        select 'C003'  CODE, 'JOB_3_3' CODE_NM, 'B03'  PARENT_ID, NULL ETC1, NULL ETC2 from dual union all 
        select 'D0001' CODE, 'JOB_4_1' CODE_NM, 'C999' PARENT_ID, 'C001' ETC1, 'C003' ETC2 from dual union all 
        select 'D0002' CODE, 'JOB_4_2' CODE_NM, 'C999' PARENT_ID, 'C001' ETC1, 'C003' ETC2 from dual union all 
        select 'D0003' CODE, 'JOB_4_3' CODE_NM, 'C999' PARENT_ID, 'C001' ETC1, 'C003' ETC2 from dual 
    ) 
SELECT LPAD(' ', 4*(LEVEL-1)) ||  CODE AS CODE, CODE_NM, PARENT_ID, LEVEL
FROM    t 
START WITH PARENT_ID = 'A'
CONNECT BY
        PRIOR CODE = PARENT_ID
OR      PRIOR CODE BETWEEN ETC1 AND ETC2
; 


CODE
CODE_NM
PARENT_ID
LEVEL


A1
JOB_1_1
A
1

    B01
JOB_2_1
A1
2

        C001
JOB_3_1
B01
3

            D0001
JOB_4_1
C999
4

            D0002
JOB_4_2
C999
4

            D0003
JOB_4_3
C999
4

A2
JOB_1_2
A
1

    B02
JOB_2_2
A2
2

        C002
JOB_3_2
B02
3

            D0001
JOB_4_1
C999
4

            D0002
JOB_4_2
C999
4

            D0003
JOB_4_3
C999
4

A3
JOB_1_3
A
1

    B03
JOB_2_3
A3
2

        C003
JOB_3_3
B03
3

            D0001
JOB_4_1
C999
4

            D0002
JOB_4_2
C999
4

            D0003
JOB_4_3
C999
4


with t as ( 
        select 'A1'    CODE, 'JOB_1_1' CODE_NM, 'A'    PARENT_ID, NULL ETC1, NULL ETC2 from dual union all 
        select 'A2'    CODE, 'JOB_1_2' CODE_NM, 'A'    PARENT_ID, NULL ETC1, NULL ETC2 from dual union all 
        select 'A3'    CODE, 'JOB_1_3' CODE_NM, 'A'    PARENT_ID, NULL ETC1, NULL ETC2 from dual union all 
        select 'B01'   CODE, 'JOB_2_1' CODE_NM, 'A1'   PARENT_ID, NULL ETC1, NULL ETC2 from dual union all 
        select 'B02'   CODE, 'JOB_2_2' CODE_NM, 'A2'   PARENT_ID, NULL ETC1, NULL ETC2 from dual union all 
        select 'B03'   CODE, 'JOB_2_3' CODE_NM, 'A3'   PARENT_ID, NULL ETC1, NULL ETC2 from dual union all 
        select 'C001'  CODE, 'JOB_3_1' CODE_NM, 'B01'  PARENT_ID, NULL ETC1, NULL ETC2 from dual union all 
        select 'C002'  CODE, 'JOB_3_2' CODE_NM, 'B02'  PARENT_ID, NULL ETC1, NULL ETC2 from dual union all 
        select 'C003'  CODE, 'JOB_3_3' CODE_NM, 'B03'  PARENT_ID, NULL ETC1, NULL ETC2 from dual union all 
        select 'D0001' CODE, 'JOB_4_1' CODE_NM, 'C999' PARENT_ID, 'C001' ETC1, 'C003' ETC2 from dual union all 
        select 'D0002' CODE, 'JOB_4_2' CODE_NM, 'C999' PARENT_ID, 'C001' ETC1, 'C003' ETC2 from dual union all 
        select 'D0003' CODE, 'JOB_4_3' CODE_NM, 'C999' PARENT_ID, 'C001' ETC1, 'C003' ETC2 from dual 
    ) 
SELECT LPAD(' ', 4*(LEVEL-1)) ||  CODE AS CODE,
       CODE_NM,
       COALESCE(PRIOR code, parent_id) AS PARENT_ID,
       LEVEL
FROM    t 
START WITH PARENT_ID = 'A'
CONNECT BY
        PRIOR CODE = PARENT_ID
OR      PRIOR CODE BETWEEN ETC1 AND ETC2
; 


CODE
CODE_NM
PARENT_ID
LEVEL


A1
JOB_1_1
A
1

    B01
JOB_2_1
A1
2

        C001
JOB_3_1
B01
3

            D0001
JOB_4_1
C001
4

            D0002
JOB_4_2
C001
4

            D0003
JOB_4_3
C001
4

A2
JOB_1_2
A
1

    B02
JOB_2_2
A2
2

        C002
JOB_3_2
B02
3

            D0001
JOB_4_1
C002
4

            D0002
JOB_4_2
C002
4

            D0003
JOB_4_3
C002
4

A3
JOB_1_3
A
1

    B03
JOB_2_3
A3
2

        C003
JOB_3_3
B03
3

            D0001
JOB_4_1
C003
4

            D0002
JOB_4_2
C003
4

            D0003
JOB_4_3
C003
4
CODE	CODE_NM	PARENT_ID	ETC1	ETC2
A1	JOB_1_1	A	null	null
A2	JOB_1_2	A	null	null
A3	JOB_1_3	A	null	null
B01	JOB_2_1	A1	null	null
B02	JOB_2_2	A2	null	null
B03	JOB_2_3	A3	null	null
C001	JOB_3_1	B01	null	null
C002	JOB_3_2	B02	null	null
C003	JOB_3_3	B03	null	null
D0001	JOB_4_1	C999	C001	C003
D0002	JOB_4_2	C999	C001	C003
D0003	JOB_4_3	C999	C001	C003