老师，这个数据怎么没有插入进去

@Test
public void testInsert(){
    SqlSession sqlSession = null;
    try{
        sqlSession = MybatisUtils.openSqlSession();
        Student student=new Student();
        student.setRegNo(20171208);
        student.setName("言豫津");
        student.setSex("男");
        student.setAge(26);
        student.setGrade("2013");
        student.setMajor("哲学系");
        int n = sqlSession.insert("stu.ins", student);
        System.out.println(n);
        System.out.println(student.getId());
    }catch (Exception e){
        e.printStackTrace();
    }finally {
        MybatisUtils.closeSession(sqlSession);
    }
}

<insert id="ins" parameterType="com.imooc.mybatis.entity.Student" >
    INSERT INTO jie.student(reg_no, name, sex, age, grade, major) VALUES (#{regNo},#{name},#{sex},#{age},#{grade},#{major})
<selectKey resultType="Integer" keyProperty="id" order="AFTER">
        select last_insert_id()
</selectKey>
</insert>

​

老师，这一条数据在数据库里没有显示啊！但是返回的n却是有值的，然后返回的id为什么是9啊？