JPA CriteriaBuilder子查询多选

我在jpa中有关于Subquery类的问题。 我需要创建带有两个自定义字段的子查询，但是子查询没有多选方法，而select方法有表达式输入参数（在查询中这是选择）和constact方法不合适。

关于加入子查询结果我也有疑问，有可能吗？ 怎么样？

我有：

连锁活动

public class Chain { @Id @Column(name = "chain_id") @GeneratedValue(generator = "seq_cha_id", strategy = GenerationType.SEQUENCE) @SequenceGenerator(name = "seq_cha_id", sequenceName = "SEQ_CHA_ID", allocationSize = 1) private Long id; @Column(name = "user_id") private Long userId; @Column(name = "operator_id") private Long operatorId; @Column(name = "subject") private String subject; @OneToMany(fetch = FetchType.LAZY, mappedBy = "chain") private List messages; @Column(name = "status") private Status status; public Long getOperatorId() { return operatorId; } public void setOperatorId(Long operatorId) { this.operatorId = operatorId; } public Status getStatus() { return status; } public void setStatus(Status status) { this.status = status; } public Long getUserId() { return userId; } public void setUserId(Long userId) { this.userId = userId; } public Long getId() { return id; } public void setId(Long id) { this.id = id; } public String getSubject() { return subject; } public void setSubject(String theme) { this.subject = theme; } public List getMessages() { return messages; } public void setMessages(List messages) { this.messages = messages; } } 

消息恩智

 public class Message { @Id @Column(name = "message_id") @GeneratedValue(generator = "seq_mess_id", strategy = GenerationType.SEQUENCE) @SequenceGenerator(name = "seq_mess_id", sequenceName = "SEQ_MESS_ID", allocationSize = 1) private Long id; @Column(name = "user_id") private Long userId; @Column(name = "message", nullable = true, length = 4000) private String message; @ManyToOne(fetch = FetchType.LAZY) @JoinColumn(name = "chain_id") private Chain chain; @Column(name = "creation_date") private Date date; @Column(name = "status") private Status status; public Long getId() { return id; } public void setId(Long id) { this.id = id; } public Long getUserId() { return userId; } public void setUserId(Long userId) { this.userId = userId; } public String getMessage() { return message; } public void setMessage(String message) { this.message = message; } public Chain getChain() { return chain; } public void setChain(Chain chain) { this.chain = chain; } public Date getDate() { return date; } public void setDate(Date date) { this.date = date; } public Status getStatus() { return status; } public void setStatus(Status status) { this.status = status; } } 

用于查询的包装器

 public class MessageWrapper { private final Long chainId; private final Long messageId; public MessageWrapper(Long chainId, Long messageId) { this.chainId = chainId; this.messageId = messageId; } } 

我需要创建这个查询（这是查询的一部分，我从谓词得到的另一部分。JPQL不合适）

 select ch.* from hl_chain ch, (select mes.CHAIN_ID, max(message_id) message_id from HL_MESSAGE mes group by chain_id) mes where mes.chain_id = ch.CHAIN_ID order by message_id; 

在子查询中我做

  Subquery subquery = criteriaQuery.subquery(MessageWrapper.class); Root subRoot = subquery.from(Message.class); subquery.select(cb.construct(MessageWrapper.class, subRoot.get(Message_.chain), cb.max(subRoot.get(Message_.id)))); 

但是，子查询没有在params中使用CompoundSelection进行选择，我不能使用CriteriaBuilder构造方法。