用户代码未连接SqlException,该怎么解决

帮我看看这段代码有错吗？
public const string Sql =
            "SELECT   ItemStatistics.Id, ItemStatistics.Xh,ItemStatistics.ItemNo, ItemStatistics.ItemName,ItemStatistics.IsDelete, ItemStatistics.AddDate, " +
            " ItemStatistics.OnUnit, Unit.UnitName AS OnUnitName, ItemStatistics.ManageUnit, ManageUnit.UnitName AS ManageUnitName, ItemStatistics.ManageDepartment, " +
            " ItemStatistics.PlanCate,ItemStatistics. ItemCate,ItemStatistics.SubCate, " +
            " ItemStatistics.ItemPi,ItemStatistics.StartDate,ItemStatistics.EndDate,ItemStatistics.Fund,"+ 
            " ItemStatistics.Status,ItemStatusForStatistics.StatusName,ItemStatistics.Remark,ItemStatistics.AcceptNo,ItemStatistics.AuthenticateNo " +
            "FROM ItemStatistics " +
            "INNER JOIN Unit ON ItemStatistics.OnUnit = Unit.Id " +
            "INNER JOIN ManageUnit ON ItemStatistics.ManageUnit = ManageUnit.Id " +
            "INNER JOIN ItemStatusForStatistics ON ItemStatistics.Status = ItemStatusForStatistics.Id ";