Return 即使外键在 HQL 中为 null 的数据

Question

我有一个 Product Table 连接 ProductCategory table 与 @ManyToOne 和 @OneToMany 关系。 Product :

@ManyToOne(fetch = FetchType.EAGER)
@JoinColumn(name = "category_id")
@NotFound(action=NotFoundAction.IGNORE)
private ProductCategory productCategory;

Category :

@OneToMany(fetch = FetchType.LAZY, mappedBy="productCategory" ,cascade = {CascadeType.MERGE, CascadeType.PERSIST, CascadeType.REFRESH})
@JsonBackReference
@OrderBy("id desc")
private Set<Product> products = new HashSet<Product>();

我有这个从 Product table:

检索数据的存储库方法

@Query("SELECT p from Product p where cast(p.id as string) like :x or p.name like :x or p.description like :x or p.sku like :x or p.productCategory.name like :x")
public Page<Product> search(@Param("x") String keyword, Pageable pageable);

此方法不会 return 类别为空的产品。即使 productCategory 列为空，如何检索产品。

Answer 1

我通过在查询中添加（实际上）LEFT JOIN 解决了问题：

"SELECT p from Product p left join p.productCategory where cast(p.id as string) like :x or p.name like :x or p.description like :x or p.sku like :x or p.productCategory.name like :x"

Return 即使外键在 HQL 中为 null 的数据

Return data even if the foreign key is null in HQL

hibernate

hql

spring-boot

jakarta-ee