为什么我的Spring数据JPA查询没有获取不同的行？

Question

我有以下实体

public class Attendance extends AbstractEntity<Long>{

    /**
     * 
     */
    private static final long serialVersionUID = -1409043060497488674L;

    @ManyToOne
    private Student student;

    @ManyToOne
    private Staff staff;

    @ManyToOne
    private Teacher teacher;

    private UserType userType;

    private Timestamp checkInTime;

    private String cardNumber;

    @ManyToOne
    private School school;

    private AttendanceStatus status;

    private AttendanceSource source;

    @ManyToOne
    private User markedBy;

    @Transient
    private long dummyId;

    public Student getStudent() {
        return student;
    }

    public void setStudent(Student student) {
        this.student = student;
    }

    public Staff getStaff() {
        return staff;
    }

    public void setStaff(Staff staff) {
        this.staff = staff;
    }

    public Teacher getTeacher() {
        return teacher;
    }

    public void setTeacher(Teacher teacher) {
        this.teacher = teacher;
    }

    public UserType getUserType() {
        return userType;
    }

    public void setUserType(UserType userType) {
        this.userType = userType;
    }

    public Timestamp getCheckInTime() {
        return checkInTime;
    }

    public void setCheckInTime(Timestamp checkInTime) {
        this.checkInTime = checkInTime;
    }

    public School getSchool() {
        return school;
    }

    public void setSchool(School school) {
        this.school = school;
    }

    public AttendanceStatus getStatus() {
        return status;
    }

    public void setStatus(AttendanceStatus status) {
        this.status = status;
    }

    public User getMarkedBy() {
        return markedBy;
    }

    public void setMarkedBy(User markedBy) {
        this.markedBy = markedBy;
    }

    public AttendanceSource getSource() {
        return source;
    }

    public void setSource(AttendanceSource source) {
        this.source = source;
    }

    public long getDummyId() {
        return dummyId;
    }

    public void setDummyId(long dummyId) {
        this.dummyId = dummyId;
    }

    public String getCardNumber() {
        return cardNumber;
    }

    public void setCardNumber(String cardNumber) {
        this.cardNumber = cardNumber;
    } 
}

我正在尝试使用以下查询获取此表的不同行：

@Query("Select  distinct a.cardNumber, a.student, a.checkInTime, a.status, a.source, a.userType from Attendance a where a.school.schoolUrl=?1 and a.userType=?2 and a.status=?3 and a.checkInTime>=?4  order by a.checkInTime desc")
List<Object[]> getTodaysStudentAttendance(String schoolUrl,UserType userType,AttendanceStatus status,Timestamp timestamp);

但无论我做什么，我都无法获取不同的行。我的数据库中有以下数据

查询返回所有这三行。我到底错过了什么？请帮忙。