In JPA 2, using a CriteriaQuery, how to count results

Question

I am rather new to JPA 2 and it\'s CriteriaBuilder / CriteriaQuery API:

CriteriaQuery javadoc

CriteriaQuery in the Java EE 6 tutorial

I would like to

Answer 1

CriteriaBuilder cb = em.getCriteriaBuilder();
CriteriaQuery cq = cb.createQuery(Long.class);
cq.select(cb.count(cq.from(MyEntity.class)));

return em.createQuery(cq).getSingleResult();