JPQL “NOT MEMBER OF” query using criteria API

问题:

Given the following JPA annotated entity classes:

@Entity
@Table("foo")
public class Foo {
    @Id private int id;
    @Column(name="name") private String name;
    @ManyToMany
    @JoinTable(name = "foo_tags",
           joinColumns = {@JoinColumn(name = "foo")},
           inverseJoinColumns = {@JoinColumn(name = "tag")})
    private Collection<Tag> tags;
    ...
}

@Entity
@Table(name = "tag")
public class Tag {
    @Id private String tag;
    ...
}

I'm trying to formulate a query to get all Foo instances that lack a given tag. The following JPQL query does the trick

SELECT f FROM Foo f WHERE :tag NOT MEMBER OF f.tags

However, I'm having trouble translating this into a criteria query. The translation seems obvious (to me):

CriteriaBuilder cb = em.getCriteriaBuilder();
CriteriaQuery<Foo> query = cb.createQuery(Foo.class);
Root<Foo> from = query.from(Foo.class);
query.where(cb.isNotMember(cb.parameter(Tag.class, "tag"), from.get(Foo_.tags)));
TypedQuery<Foo> tq = em.createQuery(query);
return tq.setParameter("tag", sometag).getResultList();

The generated SQL differs significantly in these cases though. The first query generates the following:

SELECT t0.id, t0.name FROM foo t0
WHERE NOT EXISTS (
    SELECT DISTINCT t2.TAG FROM tag t2, foo_tags t1
    WHERE (((t1.foo = t0.id) AND (t2.TAG = t1.tag)) AND ('blue' = t2.TAG)))

while the criteria query generates this:

SELECT t1.id, t1.name FROM tag t0, foo_tags t2, Foo t1
WHERE (NOT ((t0.TAG = 'blue')) AND ((t2.foo = t1.id) AND (t0.TAG = t2.tag)))

I've only tested this using the eclipselink implementation, so possibly there's a problem there, but figured I'd ask here first if anyone spots an obvious mistake.

回答1:

The SQL should be the same, although both seem like they would work (minus the empty case).

Please log a bug for the criteria issue in EclipseLink.

You should be able to use a join or a sub select instead of the special member of syntax.

SELECT f FROM Foo f left join f.tags t WHERE not(t == :tag)