java - 为什么使用@NamedEntityGraph 抛出异常？

Question

我有Spring Boot应用程序。在应用程序中存在实体：

@NamedEntityGraph(
        name = "paragraph-graph-questions",
        attributeNodes = {
                @NamedAttributeNode(value = "questions")
        })
@Entity
@Table(name = "paragraphs")
public class Paragraph {

    @Id
    private Integer id;

    @OneToMany(mappedBy = "paragraph")
    private Set<Question> questions;

    @OneToMany
    @JoinTable(
            name = "sub_paragraphs",
            joinColumns = @JoinColumn(name = "paragraph_id"),
            inverseJoinColumns = @JoinColumn(name = "sub_paragraph_id")
    )
    private Set<Paragraph> subParagraphs;
}

特点是Paragraph实体与其他段落具有反身的OneToMany关系。我制作了 JpaRepository 以便获得该段落的子段落：

@Transactional(readOnly = true)
public interface ParagraphDao extends JpaRepository<Paragraph, Integer> {

    @EntityGraph(value = "paragraph-graph-questions")
    @Query("SELECT sp FROM Paragraph p JOIN p.subParagraphs sp WHERE p.id=:id")
    Set<Paragraph> getAllSubParagraphs(int id);
}

但是如果我使用@EntityGraph这个方法，调用这个方法会抛出异常，否则方法工作正常。这是我在使用时得到的异常堆栈跟踪@EntityGraph：

org.hibernate.QueryException: query specified join fetching, but the owner of the fetched association was not present in the select list [FromElement{explicit,not a collection join,fetch join,fetch non-lazy properties,classAlias=sp,role=ru.zhenyria.deeptest.model.task.Paragraph.subParagraphs,tableName=paragraphs,tableAlias=paragraph2_,origin=paragraphs paragraph0_,columns={paragraph0_.id,className=ru.zhenyria.deeptest.model.task.Paragraph}}]

我该如何解决？谢谢。