CallDbFunction.java

Query q = em.createQuery("SELECT a, size(a.books) FROM Author a GROUP BY a.id");
List<Object[]> results = q.getResultList();

CallDbFunction.log

05:47:23,682 DEBUG [org.hibernate.SQL] -
    select
        author0_.id as col_0_0_,
        count(books1_.authorId) as col_1_0_,
        author0_.id as id1_0_,
        author0_.firstName as firstNam2_0_,
        author0_.lastName as lastName3_0_,
        author0_.version as version4_0_
    from
        Author author0_ cross
    join
        BookAuthor books1_
    where
        author0_.id=books1_.authorId
    group by
        author0_.id