标准制定者

Question

 CriteriaBuilder builder = entityManager.getCriteriaBuilder();
 //some code
criteriaQuery.where(builder.and(from.get("id").in(subquery).not(),builder.equal(from.get("status"), "FREE")));
 criteriaQuery.groupBy(from.get("room"));

在使用中如何使用builder.count（from）？