PagedResultList 这个类里的方法，是怎么拼装sql的，如果存在group by的情况是如何处理的，
这个grails底层是将hibernate封装了一下，谁懂hibernate应该也懂的吧，请指教

public int getTotalCount() {
        if (totalCount == Integer.MIN_VALUE) {
            totalCount = (Integer)hibernateTemplate.execute(new HibernateCallback<Object>() {
                public Object doInHibernate(Session session) throws HibernateException, SQLException {
                    CriteriaImpl impl = (CriteriaImpl) criteria;
                    Criteria totalCriteria = session.createCriteria(impl.getEntityOrClassName());
                    hibernateTemplate.applySettings(totalCriteria);

                    Iterator iterator = impl.iterateExpressionEntries();
                    while (iterator.hasNext()) {
                        CriteriaImpl.CriterionEntry entry = (CriteriaImpl.CriterionEntry) iterator.next();
                        totalCriteria.add(entry.getCriterion());
                    }
                    Iterator subcriteriaIterator = impl.iterateSubcriteria();
                    while (subcriteriaIterator.hasNext()) {
                        CriteriaImpl.Subcriteria sub = (CriteriaImpl.Subcriteria) subcriteriaIterator.next();
                        totalCriteria.createAlias(sub.getPath(), sub.getAlias(), sub.getJoinType(), sub.getWithClause());
                    }
                    totalCriteria.setProjection(impl.getProjection());
                    totalCriteria.setProjection(Projections.rowCount());
                    return ((Number)totalCriteria.uniqueResult()).intValue();
                }
            });
        }
        return totalCount;
    }