Oracle 18c

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CREATE TABLE depts ( DEPT_ID, DEPT_NAME, DEPT_PARENT ) AS
SELECT 5500, 'World',           NULL FROM DUAL UNION ALL
SELECT 5510, 'Region 1',        5500 FROM DUAL UNION ALL
SELECT 5511, 'Cell 1 Region 1', 5510 FROM DUAL UNION ALL
SELECT 5512, 'Cell 2 Region 1', 5510 FROM DUAL UNION ALL
SELECT 5513, 'Cell 3 Region 1', 5510 FROM DUAL UNION ALL
SELECT 5514, 'Cell 4 Region 1', 5510 FROM DUAL UNION ALL
SELECT 5515, 'Cell 5 Region 1', 5510 FROM DUAL UNION ALL
SELECT 5520, 'Region 2',        5500 FROM DUAL UNION ALL
SELECT 5521, 'Cell 1 Region 2', 5520 FROM DUAL UNION ALL
SELECT 5522, 'Cell 2 Region 2', 5520 FROM DUAL UNION ALL
SELECT 5530, 'Region 3',        5500 FROM DUAL UNION ALL
SELECT 5531, 'Cell 1 Region 3', 5530 FROM DUAL UNION ALL
SELECT 5532, 'Cell 2 Region 3', 5530 FROM DUAL UNION ALL
SELECT 5540, 'Region 4',        5500 FROM DUAL UNION ALL
SELECT 5533, 'Cell 1 Region 4', 5540 FROM DUAL UNION ALL
SELECT 5534, 'Cell 2 Region 4', 5533 FROM DUAL UNION ALL
SELECT 5590, 'Region 5',        5500 FROM DUAL UNION ALL
SELECT 5591, 'Cell 1 Region 5', 5590 FROM DUAL;

18 rows affected

ANCESTOR	DEPT_ID	PATH
5500	5510	>5500>5510
5500	5511	>5500>5510>5511
5500	5512	>5500>5510>5512
5500	5513	>5500>5510>5513
5500	5514	>5500>5510>5514
5500	5515	>5500>5510>5515
5500	5520	>5500>5520
5500	5521	>5500>5520>5521
5500	5522	>5500>5520>5522
5500	5530	>5500>5530
5500	5531	>5500>5530>5531
5500	5532	>5500>5530>5532
5500	5540	>5500>5540
5500	5533	>5500>5540>5533
5500	5534	>5500>5540>5533>5534
5500	5590	>5500>5590
5500	5591	>5500>5590>5591
5510	5511	>5510>5511
5510	5512	>5510>5512
5510	5513	>5510>5513
5510	5514	>5510>5514
5510	5515	>5510>5515
5520	5521	>5520>5521
5520	5522	>5520>5522
5530	5531	>5530>5531
5530	5532	>5530>5532
5533	5534	>5533>5534
5540	5533	>5540>5533
5540	5534	>5540>5533>5534
5590	5591	>5590>5591