If you want to query from two tables with a full outer join, you can use the FULL OUTER JOIN ... ON clause in the FROM clause. The following query returns output with a full outer join from two tables: departments and employees. The join condition is that the manager ID in the departments table equals to the employee ID in the employees table:

SQL> set NULL 'NULL'

SQL> SELECT d.department_name, e.first_name, e.last_name

2 FROM departments d FULL OUTER JOIN employees e

3 ON d.manager_id = e.employee_id;