Spring JPA @Query如何连接子表和父表？

@Entity
@Table(name = "parent_table")
public class ParentEntity {
    @Id
    @GeneratedValue(strategy = GenerationType.IDENTITY)
    private Long id;

    // 其他属性和关联关系
}

@Entity
@Table(name = "child_table")
public class ChildEntity {
    @Id
    @GeneratedValue(strategy = GenerationType.IDENTITY)
    private Long id;

    @ManyToOne
    @JoinColumn(name = "parent_id")
    private ParentEntity parent;

    // 其他属性
}

@Repository
public interface ParentRepository extends JpaRepository<ParentEntity, Long> {
    @Query("SELECT p FROM ParentEntity p JOIN FETCH p.children c WHERE p.id = :parentId")
    ParentEntity findParentWithChildren(@Param("parentId") Long parentId);
}