我在编写 JPQL 查询时遇到了棘手的情况,以下是我的表格:-
订单_
order_id quotation_id 1 11 2 12
Quotation
q_id qr_id 11 101 12 102
QRequest
qr_id name 101 Name 1 102 Name 2
@Entity
@Table(name = "Order_")
public class Order {
@Id
@GeneratedValue
private long id;
@OneToOne(cascade = CascadeType.ALL)
@JoinColumn(name = "q_id", unique = true)
private Quotation quotation;
}
@Entity
public class QRequest {
@Id
@GeneratedValue
private long id;
@Column(nullable = false)
private String name;
}
@Entity
public class Quotation {
@Id
@GeneratedValue
private long id;
@ManyToOne(cascade = CascadeType.ALL)
@JoinColumn(name = "qr_id", nullable = false)
private QRequest qRequest;
}
public List<QRequest> getQRequestForOrders(List<Long> orderIds) {
String query = "Select qr from QRequest qr, Quotation q, Order o " +
"where o.quotation.qRequest.id = qr.id " +
"and o.id in (:orderIds) ";
TypedQuery<QRequest> typedQuery = entityManager.createQuery(query, QRequest.class);
typedQuery.setParameter("orderIds", orderIds);
return typedQuery.getResultList();
}
我正在尝试获取 List<QRequest>
来自List
的order_id
。
这是 SQL 等效查询:-
select qr.* from QRequest qr
inner join Quotation q on q.qr_id = qr.id
inner join Order_ o on o.quotation_id = q.id
where o.id in (1,2);
我正在寻找等效的 JPQL 查询。
最佳答案
在这种情况下,可能值得设置双向关系以使其更易于查询,例如:
@Entity
public class QRequest {
@Id
@GeneratedValue
private long id;
@Column(nullable = false)
private String name;
@OneToMany(mappedBy = "qRequest")
private Quotation quotation;
}
@Entity
public class Quotation {
@Id
@GeneratedValue
private long id;
@ManyToOne(cascade = CascadeType.ALL)
@JoinColumn(name = "qr_id", nullable = false)
private QRequest qRequest;
}
"Select qr from QRequest qr " +
"join qr.quotation q "
如果你想避免它,你可以改为
"Select qr from QRequest qr, Quotation q, Order o " +
"where o.quotation.qRequest.id = qr.id " +
"and o.quotation.id = q.id " +
"and o.id in (:ids) "
和.setParameter("ids", your_list);
在这两种情况下,查询都会返回QRequest
的集合
关于java - JPQL内连接查询,我们在Stack Overflow上找到一个类似的问题: https://stackoverflow.com/questions/49977250/