SELECT COLS.[name] + ',' + ' '
FROM sys.index_columns IXCOLS
 INNER JOIN sys.columns COLS
   ON  IXCOLS.column_id   = COLS.column_id
   AND IXCOLS.[object_id] = COLS.[object_id]
WHERE IXCOLS.is_included_column = 0
 AND IDX.[object_id] = IXCOLS.[object_id] 
 AND IDX.index_id = IXCOLS.index_id
ORDER BY key_ordinal
FOR XML PATH('')
) AS index_columns_key,

SELECT COLS.[name] + case when IXCOLS.is_descending_key = 0 then ' asc' else ' desc' end + ',' + ' '
FROM sys.index_columns IXCOLS
 INNER JOIN sys.columns COLS
   ON  IXCOLS.column_id   = COLS.column_id
   AND IXCOLS.[object_id] = COLS.[object_id]
WHERE IXCOLS.is_included_column = 0
 AND IDX.[object_id] = IXCOLS.[object_id] 
 AND IDX.index_id = IXCOLS.index_id
ORDER BY key_ordinal
FOR XML PATH('')
) AS index_columns_key,