如何为多对多关联编写 HQL 查询

Question

所以我花了几个小时尝试为多对多关系编写 HQL 查询。即使在阅读了休眠文档之后，我尝试过的所有查询都没有任何效果。有人可以帮助我吗？提前谢谢你。

我尝试过内连接、连接和外连接，有或没有 fetch。我认为这个问题可能与香水类中的一对多关系有关。

@Query("FROM Category c INNER JOIN FETCH c.fragrances f WITH c.referencedId = 1")
List<Category> getCatalog();

没有 get/setter 的类别类

@Entity
public class Category extends AbstractEntity {

   @Column(name = "name", nullable = false)
   private String name;

   @ManyToMany(fetch = FetchType.EAGER, cascade = CascadeType.ALL)
   @JoinTable(name = "Category_has_Fragrance",
        joinColumns = @JoinColumn(name = "category_id"),
        inverseJoinColumns = @JoinColumn(name = "fragrance_id")
   )
   @OrderBy("name")
   private List<Fragrance> fragrances;

   @Column(name = "referenced_id", nullable = false)
   private int referencedId;
]

没有 get/setter 的 Fragrance 类

@Entity
public class Fragrance extends AbstractEntity {

    @Column(name = "name", nullable = false)
    private String name;

    @Column(name = "description", nullable = false)
    private String description;

    @ManyToMany(fetch = FetchType.EAGER, cascade = CascadeType.ALL, mappedBy = "fragrances")
    private Set<Category> categories;

    @OneToMany(fetch = FetchType.EAGER, cascade = CascadeType.ALL, mappedBy = "fragrance")
    private List<FragrancedProduct> fragrancedProducts;

    @Column(name = "image_path")
    private String imagePath;
}

Answer 1

试试这个：

select c from Category c join c.fragrances f where c.referencedId = :id

你可以在这里查看类似的问题：How do I do with HQL, many to many?