Java 如何从Spring数据JPA返回自定义对象include ManyToMany

我正试图通过JPQL获得一个自定义对象。 如果我在JPQL上使用“fetch”，我可以得到一个关系表。但是如果我对自定义对象使用JPQL，我就无法从关系表中获取该对象

是否可以在以下实体配置中的自定义对象中包含多个对象

@Entity
class Student {
 
    @Id
    Long id;
 
    @ManyToMany
    @JoinTable(name = "student_course_relation", joinColumns = {
            @JoinColumn(name = "student_id") }, inverseJoinColumns = { @JoinColumn(name = "course_id") })
    Set<Course> likedCourses;
 
    // additional properties
    // standard constructors, getters, and setters
}
 
@Entity
class Course {
 
    @Id
    Long id;
 
    @ManyToMany(mappedBy = "likedCourses")
    Set<Student> likes;
 
    // additional properties
    // standard constructors, getters, and setters
}

未创建列

请告诉我解决办法

多谢各位

// custom object

class StudentCourses {

    Long id;

    Set<Course> likedCourses;

    // additional properties
    // standard constructors, getters, and setters
}

public interface StudentRepository extends JpaRepository<Student, Long> {

@Query(
            "select " +
            "new com.example.StudentCourses ( " +
            "s.id, " +
            "s.likedCourses" +
            ") "+
            "from " +
            "Student s " +
)
List<StudentCourses> findAll();
}

//error log

    select
        student.id as col_0_0_,
        . as col_15_0_  //← cause of error
    from
        student student0_ cross 
    inner join
        student_course_relation student2_ 
            on student0_.id=student_course_relation.student_id 

org.postgresql.util.PSQLException: ERROR: syntax error at or near "."

...continue logs