我有以下名为产品的实体:
@Id
@SequenceGenerator(name = "Product_seq", sequenceName = "PRODUCT_SEQ", allocationSize = 1)
@GeneratedValue(strategy=GenerationType.SEQUENCE, generator = "Product_seq")
@Column(name = "ID")
private Long id;
@OneToOne
@JoinColumn(name = "CAS_ID")
private CAS cas;
...
还有一个 CAS 实体:
@Id
@SequenceGenerator(name = "CAS_seq", sequenceName = "CAS_SEQ", allocationSize = 1)
@GeneratedValue(strategy=GenerationType.SEQUENCE, generator = "CAS_seq")
@Column(name = "ID", unique = true, nullable = false, scale = 0)
private Long id;
@Column(name = "CAS_NUMBER", length = 6)
private String casNumber;
@Column(name = "CAS_DESCRIPTION")
private String casDescription;
...
在我的应用程序中，我有以下 HQL 语句:
select p from Product p where p.approve IS NULL order by p.cas.casNumber desc
这里的问题是 p.cas.casNumber 可以为 NULL，我也需要返回这些行。我不知道如何使用 p.cas.casNumber 在此表上编写 LEFT JOIN。
感谢您提供的任何帮助。谢谢!
最佳答案
您可以尝试如下:
select p from Product p left join p.cas as a where p.approve IS NULL order by a.casNumber desc
关于java - hibernate HQL : Left Join with OnetoOne，我们在Stack Overflow上找到一个类似的问题： https://stackoverflow.com/questions/21442221/