Why using SQLITE where clause does not work?

I am trying to create a SQLITE query like this (first approach):

        int count;
        using ( var db = new SQLiteConnection( new SQLitePlatformWinRT(), DbPath ) )
            {
            count = ( from p in db.Table<TickRecord>()
                      where (p.TickStartDate.LocalDateTime >= start && p.TickEndtDate.LocalDateTime <= end )
                      select (int)p.DurationInSeconds ).Sum();
            }
        return count;

When running the query the application crash on the where clause.

I was able to achieve it like this (second approach):

        ObservableCollection<TickRecord> records;

        // Create a new connection
        using ( var db = new SQLiteConnection( new SQLitePlatformWinRT(), DbPath ) )
           {
           records = new ObservableCollection<TickRecord>( db.Table<TickRecord>().Select( i => i ) );
           }

        int count = records.Where( record => record.TickStartDate.LocalDateTime >= start && record.TickEndDate.LocalDateTime <= end ).Sum( record => record.DurationInSeconds );

Is there a way to achieve the same using my first approach?

Thx