ActiveRecord group by query

One day , I need use "group by " query,
but i don't know how to write it on ActiveRecord,

I try mony method, but i can't get the results. i am also post a thread to forum of caslte, but no one replay it ,may be it is so easy.
so ,  i redo my work. i found ,
i can use

            " select   table .name, count ( table .name)  from   Table   table   group   by   table .name  order   by   table   count ( table .name)  desc "

My gold, Is correct now.

HqlBasedQuery query  =   new  HqlBasedQuery( typeof (ActivityInfo), hql);
             return  ExecuteQuery(query);

How to get the data? like below

 ArrayList list  =  o  as  ArrayList;
         for ( int  i = 0 ;i < list.Count;i ++ )
         {
           object[] list2 = list[i] as object[];
        }

and I found in activeRecord you can use SQL language to query, just set QueryLanguage to sql,

anthor method: Navtie Query

ISessionFactoryHolder sessionHolder  =  ActiveRecordMediator.GetSessionFactoryHolder(); ISession session  =  sessionHolder.CreateSession( typeof (Synonym));  try   { string query = ""; IQuery sqlQuery = session.CreateSQLQuery(query, "Synonym", typeof(Synonym)); sqlQuery.SetMaxResults(10); return sqlQuery.List(); }   finally   { sessionHolder.ReleaseSession(session); }