NHibernate读取单个字段值，错误修改方法

 原语句：

            IQuery query = DbHelper.Session.CreateQuery("select Id from Member where UserName=:username");
            query.SetString("username", username);
            object reslut = query.UniqueResult();

 

读取单个字段值，报如下错误：

undefined alias or unknown mapping: Id

 

修正语句

            IQuery query = DbHelper.Session.CreateQuery("select member.Id from Member as member where UserName=:username");
            query.SetString("username", username);
            object reslut = query.UniqueResult();

 

读取单个字段时，要注意加上别名，程序正常通过。