Spring JPA数据获取联接重复值

Question

我需要通过课程ID获取一些课程。我随课程参加课程，并且符合我的期望。但是当我离开联接获取以防止查询N + 1时。我的结果是重复的。

以下是代码重复的结果：

 @Query(value = "SELECT m " +
    "FROM YtClass m " +
    " INNER JOIN FETCH m.course c " +
    " LEFT JOIN FETCH m.classStudents cs " +
    " LEFT JOIN FETCH cs.student " +
    " LEFT JOIN FETCH m.classSubjects css " +
    " LEFT JOIN FETCH css.subject  " +
    "WHERE c.id = :courseId AND m.status = :status",
    countQuery = "SELECT count(m.id) FROM YtClass m WHERE m.course.id = :courseId AND m.status = :status")
  Page<YtClass> findAllByCourseId(
@Param("courseId") String courseId, @Param("status") String status, Pageable pageable);

这是正确的结果：（查询N + 1个问题）

 @Query(value = "SELECT m " +
    "FROM YtClass m " +
    " INNER JOIN FETCH m.course c " +
    "WHERE c.id = :courseId AND m.status = :status",
    countQuery = "SELECT count(m.id) FROM YtClass m WHERE m.course.id = :courseId AND m.status = :status")
  Page<YtClass> findAllByCourseId(
@Param("courseId") String courseId, @Param("status") String status, Pageable pageable);