mysql - Hibernate - 连接查询

Question

我有两门课:

@Entity
public class Tick {

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

@ManyToOne(optional = false)
@JoinColumn(name = "elitesystem_id", referencedColumnName = "id")
private EliteSystem eliteSystem;

private Date createDate;

@ManyToOne(optional = true)
@JoinColumn(name = "commander_id", referencedColumnName = "id")
private Commander commander;

private String address;

和

@Entity
public class Note {

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

@ManyToOne(optional = true)
@JoinColumn(name = "tick_id", referencedColumnName = "id")
private Tick tick;

private String text;

private Date createDate;

我想选择所有刻度并获取注释(如果有):

    Query query = session.createQuery("select t, n from Note n right join n.tick t where t.commander.name = '123'");
    List<Object[]> list = query.list();

这仅返回 Tick 对象。在 1 个查询中获取注释信息的正确方法是什么？我可以将对 Note 的引用放入 Tick 类中，但这听起来不对，因为只有几个注释，所以 Tick 表中的列大部分是空的。

Answer 1

创建一个新类，例如:

public class TickNote {
    private Tick tick;
    private Note note;

    public TickNote(Tick tick,Note note){
        this.tick=tick;
        this.note=note;

那么您的查询是:

Query query = session.createQuery("select NEW TickNote(t, n) from Note n right join n.tick t where t.commander.name = '123'");
    List<TickNote> list = query.list();