CAML query on folders

Querying on a list for particular folder:

private DataTable GetDataTable(SPList list)

        {

            DataTable dt = new DataTable();

            SPQuery qry = new SPQuery();

            try

            {

                string relativeURL = list.RootFolder.Url;

                qry.Query = "<Where><Eq><FieldRef Name='FileDirRef'/><Value Type='Lookup'>" + relativeURL + "/my folder/my next folder</Value></Eq></Where>";

                qry.ViewAttributes = "Scope='RecursiveAll'";

                SPListItemCollection coll = list.GetItems(qry);

                dt = coll.GetDataTable();

            }

            catch (Exception ex)

            {

                MessageBox.Show(ex.Message.ToString());

            }

            return dt;

        }

we can use various properties for "Scope=''".
1. Default
2. Recursive
3. RecursiveAll