怎样检查fragmentation

SELECT dbschemas.[name] AS ‘Schema‘, 
 dbtables.[name] AS ‘Table‘, 
 dbindexes.[name] AS ‘Index‘,
 indexstats.index_type_desc,
 indexstats.avg_fragmentation_in_percent,
 indexstats.page_count
FROM sys.dm_db_index_physical_stats (DB_ID(), NULL, NULL, NULL, NULL) AS indexstats
INNER JOIN sys.tables dbtables ON (dbtables.[object_id] = indexstats.[object_id])
INNER JOIN sys.schemas dbschemas ON (dbtables.[schema_id] = dbschemas.[schema_id])
INNER JOIN sys.indexes AS dbindexes ON (dbindexes.[object_id] = indexstats.[object_id]
AND indexstats.index_id = dbindexes.index_id)
WHERE indexstats.database_id = DB_ID()
ORDER BY indexstats.avg_fragmentation_in_percent DESC