linq 查询

  

   是否存在没有设置佣金的房型
        public bool IfHaveNoCommionSet(long companyid)
        {
            HotelDataClasses hoteldata = new HotelDataClasses();
            var model = from c in hoteldata.HotelRoomInfo
                        join o in hoteldata.Htel_CheckOutRoom on c.RoomCode equals o.RoomCode into hinfo
                        from info in hinfo.DefaultIfEmpty()
                        where info.ID == null
                        where c.CompanyID ==177
                        select info;
            var ddd = model.ToList();

            string aaa = model.Count().ToString();

            if (model.Count() > 0) return true;

            else return false;

        }

这里边是个表连接查询。主表是房间表，5个记录，从表是Htel_CheckOutRoom  1条数据。查询返回的数目为5-1=4；