mybatis一对多

一.课程包含课时

xml如下：

  <resultMap id="culTrainCoursePO" type="com.thinkgem.jeesite.modules.train.entity.CulTrainCoursePO">
    <id column="id" jdbcType="VARCHAR" property="id" />
    <result column="course_name" jdbcType="VARCHAR" property="courseName" />
    <result column="bel_project_id" jdbcType="VARCHAR" property="belProjectId" />
   
    <collection property="culTrainLessonPOs" ofType="com.thinkgem.jeesite.modules.train.entity.CulTrainLessonPO">
      <id property="id" column="lesson_id"/>
      <result property="courseId" column="course_id"/>
      <result property="lessonBatchNum" column="lesson_batch_num"/>
     
    </collection>
  </resultMap>


  <select id="selectCourseLessonById" parameterType="String" resultMap="culTrainCoursePO">
    select c.*,l.id lesson_id,l.course_id,l.lesson_batch_num from
    cul_train_course c left join cul_train_lesson l on l.course_id = c.id
    where c.id = #{id}
  </select>
    
  <select id="selectCourseLesson" resultMap="culTrainCoursePO">
    select c.*,l.id lesson_id,l.course_id,l.lesson_batch_num from
    cul_train_course c left join cul_train_lesson l on l.course_id = c.id
  </select>

参考来源：https://blog.csdn.net/qq_36791569/article/details/81517080