Whаt will this cоde dо if the emplоyee ID аlreаdy exists? MERGE INTO employees eUSING new_employees nON (e.employee_id = n.employee_id)WHEN MATCHED THEN UPDATE SET e.salary = n.salaryWHEN NOT MATCHED THEN INSERT (employee_id, employee_name, salary) VALUES (n.employee_id, n.employee_name, n.salary);