我有一个我使用的所有不同帐户名称前缀(a-z)的列表

var accounts = this.SessionManager.GetActiveSession().QueryOver<Account>();

var q = accounts.Select(Projections.Distinct(
        Projections.sqlFunction("substring",NHibernateUtil.String,Projections.Property("Name"),Projections.Constant(1),Projections.Constant(1))));

@H_403_4@但是,我想要做的不是返回一个不同的列表,而是将前缀分组,并返回以该前缀开头的帐号数,但我不确定如何使用查询来执行组,因为它不像标准那样简单LINQ.

@H_403_4@我使用QueryOver而不是Query的原因是因为某些原因,子串函数正在内存中执行而不是在数据库服务器上执行.

@H_403_4@这就是我通常会这样做的方式

var prefixes = (from acc in this.SessionManager.GetActiveSession().Query<Account>()
              group acc by acc.Name.Substring(0,1)
              into grp
              select new
                       {
                         Prefix = grp.Key,Count = grp.Count()
                       });

@H_403_4@编辑这是我尝试但我收到以下错误

@H_403_4@表达式中无法识别的方法调用sqlFunction(“substring”,new [] {Property(“Name”),Constant(Convert(1)),Constant(Convert(1))})

var accounts = this.SessionManager.GetActiveSession().QueryOver<Account>().Select(
            Projections.Group<string>(x => Projections.sqlFunction("substring",Projections.Constant(1))),Projections.Count<string>(x => Projections.sqlFunction("substring",Projections.Constant(1)))

          );

var accounts = _busDb.Session.QueryOver<QueueEntity>()
        .Select(
            Projections.sqlGroupProjection(
                "SUBSTRING({alias}.Name,1) as FirstChar","SUBSTRING({alias}.Name,1)",new[] {"FirstChar"},new[] {NHibernateUtil.String}),Projections.Count("id"));