JPA JPQL: select items when attribute of item (list/set) contains another item

Question

public class Document extends Model {
... 
@ManyToMany
public Set accessors;
...
}

I want to select all Documents which accessors conta

Answer 1

select distinct d from Document d inner join d.accessors a where a.id = :id

You should learn how SQL joins work, and then learn how to use joins in JPQL. That's essential. You'll find plenty of tutorials online. Google is your friend.