title: how to implement Subqueries.rowCount(DetachedCriteria dc)
body: <p>When a DetachedCrieria has projections, how to get the row count of the DetachedCriteria result set?  For HQL:</p>
  
  <p>select count(*) from (select name, sum(grade) from score group by name).</p>
  
  <p>For hibernate, how to implement Subqueries.rowCount(DetachedCriteria dc)? Thanks.</p>