Oracle 23c

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CREATE TABLE t(
   User_id   number(6)
  ,Usr        VARCHAR2(20)
  ,Department  VARCHAR2(50)
  ,id_depto  number(6)
  ,id_manage number(6)
);
INSERT INTO t(User_id,Usr,Department,id_depto,id_manage) VALUES (165,'Jhonson','Purchasing management',900,900);
1 rows affected

INSERT INTO t(User_id,Usr,Department,id_depto,id_manage) VALUES (356,'David','purchasing department R1',343,900);
1 rows affected

INSERT INTO t(User_id,Usr,Department,id_depto,id_manage) VALUES (545,'Mary','purchasing department R2',326,900);
1 rows affected

INSERT INTO t(User_id,Usr,Department,id_depto,id_manage) VALUES (825,'Alexander','Finance department',925,800);
1 rows affected

select * from t;


USER_ID
USR
DEPARTMENT
ID_DEPTO
ID_MANAGE


165
Jhonson
Purchasing management
900
900

356
David
purchasing department R1
343
900

545
Mary
purchasing department R2
326
900

825
Alexander
Finance department
925
800


select *
from t
union all
select x.user_id, x.usr, x.department, t.id_depto, t.id_manage
from t
join t x on x.id_depto = x.id_manage 
        and x.id_depto = t.id_manage 
        and x.user_id <> t.user_id
order by 1


USER_ID
USR
DEPARTMENT
ID_DEPTO
ID_MANAGE


165
Jhonson
Purchasing management
900
900

165
Jhonson
Purchasing management
326
900

165
Jhonson
Purchasing management
343
900

356
David
purchasing department R1
343
900

545
Mary
purchasing department R2
326
900

825
Alexander
Finance department
925
800

USER_ID	USR	DEPARTMENT	ID_DEPTO	ID_MANAGE
165	Jhonson	Purchasing management	900	900
356	David	purchasing department R1	343	900
545	Mary	purchasing department R2	326	900
825	Alexander	Finance department	925	800