hibernate - jpql order by 子查询产生意外的 AST 节点异常

Question

我将一个工作 (postgre)sql 查询转换为 jpql，但 hibernate 抛出了

org.hibernate.hql.ast.QuerySyntaxException: unexpected AST node exception

这些是我的核心模型类:

@Entity
public class Piece {
    @Id
    @GeneratedValue
    public Long id;

    @ManyToOne
    public AUser user;
    public long index;
...
}

@Entity
public class Vote {
    @Id
    @GeneratedValue
    public Long id;

    @ManyToOne
    public AUser receiver;
...
}

@Entity
public class AUser {
    @Id
    @GeneratedValue
    public Long id;

    @OneToMany(mappedBy="receiver", cascade=CascadeType.ALL)
    public List<Vote> receivedVotes;
...
}

这是我的 jpql 查询:

String query = "select p from Piece p order by (select count(v.receiver) from Vote v where v.receiver.id=p.user.id) desc, p.index";

谁能解释一下这个异常，为什么会发生以及如何更改查询以避免它。谢谢!

Answer 1

JPQL 不支持 order by 中的子查询。如果我正确理解您的查询，您可以尝试如下操作:

select p 
from Piece p left join p.user.receivedVotes rv
group by p
order by count(rv) desc, p.index