select *
  from (select v.sql_id,
	  v.child_number,
	  v.sql_text,
	  v.elapsed_time,
	  v.cpu_time,
	  v.disk_reads,
	  rank() over(order by v.elapsed_time desc) elapsed_rank
          from v$sql v) a
 where elapsed_rank <= 10;

select *
  from (select v.sql_id,
	  v.child_number,
	  v.sql_text,
	  v.elapsed_time,
	  v.cpu_time,
	  v.disk_reads,
	  rank
 
() over(order by v.cpu_time desc) elapsed_rank
          from v$sql v) a
 where elapsed_rank <= 10;

select *
  from (select v.sql_id,
	  v.child_number,
	  v.sql_text,
	  v.elapsed_time,
	  v.cpu_time,
	  v.disk_reads,
	  rank() over(order by v.disk_reads desc) elapsed_rank
          from
 
 v$sql v) a
 where elapsed_rank <= 10;

轉自： http://www.tuicool.com/articles/v2Mfii