Server Error in '/' Application.

SELECT  tbl_ebooks.*,(select fld_title from tbl_grade where  fld_id= tbl_ebooks.fld_gradeID) as Grade FROM  tbl_ebooks WHERE fld_active=1 and  fld_subID in (SELECT fld_id from tbl_subject where fld_type=)   and fld_gradeID in (1,2) and fld_country=-1 <br>Incorrect syntax near ')'.

Description: An unhandled exception occurred during the execution of the current web request. Please review the stack trace for more information about the error and where it originated in the code.

Exception Details: System.Exception: SELECT  tbl_ebooks.*,(select fld_title from tbl_grade where  fld_id= tbl_ebooks.fld_gradeID) as Grade FROM  tbl_ebooks WHERE fld_active=1 and  fld_subID in (SELECT fld_id from tbl_subject where fld_type=)   and fld_gradeID in (1,2) and fld_country=-1 <br>Incorrect syntax near ')'.

Source Error:


Line 64:             catch (Exception ex)
Line 65:             {
Line 66:                 throw new Exception(sqlStr + " <br>" + ex.Message);
Line 67:             }
Line 68:             finally

Source File: c:\WebServer\areeg\App_Code\Cdb.cs    Line: 66

Stack Trace:


[Exception: SELECT  tbl_ebooks.*,(select fld_title from tbl_grade where  fld_id= tbl_ebooks.fld_gradeID) as Grade FROM  tbl_ebooks WHERE fld_active=1 and  fld_subID in (SELECT fld_id from tbl_subject where fld_type=)   and fld_gradeID in (1,2) and fld_country=-1 <br>Incorrect syntax near ')'.]
   Cdb.OleExecDataSet(String sqlStr) in c:\WebServer\areeg\App_Code\Cdb.cs:66
   ebooks.selectHebook(String Type, String GradeId, String CountryID) in c:\WebServer\areeg\App_Code\ebooks.cs:171
   Seraj_Gsubject.Fillebook(String SubID, String GradeID, String CountryId) in c:\WebServer\areeg\e-book.aspx.cs:82
   Seraj_Gsubject.Page_Load(Object sender, EventArgs e) in c:\WebServer\areeg\e-book.aspx.cs:49
   System.Web.UI.Control.OnLoad(EventArgs e) +108
   System.Web.UI.Control.LoadRecursive() +90
   System.Web.UI.Page.ProcessRequestMain(Boolean includeStagesBeforeAsyncPoint, Boolean includeStagesAfterAsyncPoint) +1533


Version Information: Microsoft .NET Framework Version:4.0.30319; ASP.NET Version:4.8.4110.0