set serveroutput on

declare

v_salary employees.salary%type;

select salary into v_salary

from employees

where employee_id = 120;

update employees set salary = ( select salary from employees where employee_id = 130)

where employee_id = 120;

update employees set salary = v_salary

where employee_id = 130;

commit;

dbms_output.put_line('Interchanged successfully!');

end;