Oracle Merge无法提交

Question

我正在我的项目中使用oracle merge命令。当我执行它时，只有更新和删除命令工作正常。没有新行添加到目标表虽然它没有匹配的行。我应该配置任何东西我的目标表？

MERGE INTO customer b 
   USING (SELECT employee_id, salary, dept_no 
          FROM employee 
          WHERE dept_no =20) e 
   ON(b.employee_id = e.employee_id) 
WHEN MATCHED THEN 
   UPDATE SET b.bonus = e.salary * 0.1 
   DELETE WHERE (e.salary < 40000) 
WHEN NOT MATCHED THEN 
   INSERT (b.employee_id, b.bonus) 
       VALUES (e.employee_id, e.salary * 0.05) 
       WHERE (e.salary > 40000);