-- https://docs.oracle.com/en/database/oracle/oracle-database/23/sqlrf/Hierarchical-Queries.html
UPDATE employees SET manager_id = 145
   WHERE employee_id = 100;
SELECT last_name "Employee", 
   LEVEL, SYS_CONNECT_BY_PATH(last_name, '/') "Path"
   FROM employees
   WHERE level <= 3 AND department_id = 80
   START WITH last_name = 'King'
   CONNECT BY PRIOR employee_id = manager_id AND LEVEL <= 4;