Question

目标是检索已向特定用户（当前登录用户）发送消息的所有用户（而非消息），或已收到该用户的消息（即使他们尚未回复）。我尝试了很多查询，但无济于事。（我有登录用户的ID）。

你有什么想法吗？我假设我需要加入Message＆amp;已注册的用户类，但不确定它是如何工作的，因为消息具有'发送者'和＆amp; 'receiver'使查询更复杂一些。

RegisteredUser类（没有对Message的引用）：

@Entity
@Table(name = "USER")
public class RegisteredUser implements Serializable {

    @Id
    @GeneratedValue(strategy = GenerationType.IDENTITY)
    private int id;

消息类：

@Entity
@Table(name = "MESSAGE")
public class Message implements Serializable {

    @Id
    @GeneratedValue(strategy = GenerationType.IDENTITY)
    int id;

    @ManyToOne
    @JoinColumn(name = "receiverId")
    RegisteredUser receiver;

    @ManyToOne
    @JoinColumn(name = "senderId")
    RegisteredUser sender;

我正在使用jpa 2.0和hibernate 3.5.6。

谢谢！

//编辑 - 解决方案，感谢Andrey

"select distinct u from RegisteredUser u where u in (select m1.sender from Message m1 join m1.receiver r where r.id = " + user.getId() + ") or u in (select m2.receiver from Message m2 join m2.sender s where s.id = " + user.getId() + ")"

Answer 1

select distinct u from RegisteredUser u where 
u in (select m1.sender from Message m1 join m1.receiver r where r.id = " + user.getId() + ") or
u in (select m2.receiver from Message m2 join m2.sender s where s.id = " + user.getId() + ")"

JPA / Hibernate加入查询

1 个答案: