JPA: Find all articles that have a common set of tags

Question

I have the following entities:

@Entity
public class Article{
    @Id
    private String id;

    @ManyToMany(cascade = CascadeType.PERSIST)
    private Set&l         


        

Answer 1

select a from Article a where :numberOfTags = 
    (select count(distinct tag.id) from Article a2
     inner join a2.tags tag
     where tag in :tags
     and a = a2)

This basically counts the tags of the articles that are tags in the accepted set of tags, and if the number of such tags is eaqual to the size of the accepted set of tags (meaning that all tags in the set are tags of the article), returns the article.