SQLServer查询耗时sql语句

SELECT TOP 50
qs.total_worker_time/qs.execution_count as [Avg CPU Time],
SUBSTRING(qt.text,qs.statement_start_offset/2, 
(case when qs.statement_end_offset = -1 
then len(convert(nvarchar(max), qt.text)) * 2 
else qs.statement_end_offset end -qs.statement_start_offset)/2) 
as query_text,
qt.dbid, dbname=db_name(qt.dbid),
qt.objectid 
FROM sys.dm_exec_query_stats qs
cross apply sys.dm_exec_sql_text(qs.sql_handle) as qt
ORDER BY [Avg CPU Time] DESC