1 -- 执行最慢的sql
 2 SELECT *
 3 FROM (SELECT sa.sql_TEXT, 4             sa.sql_FULLTEXT, 5             sa.EXECUTIONS as "exeCount", 6             ROUND(sa.ELAPSED_TIME / 1000000,2) as "execTimeTotal", 7             ROUND(sa.ELAPSED_TIME / 1000000 / sa.EXECUTIONS,2) as "execTimeAvg", 8             sa.COMMAND_TYPE, 9             sa.PARSING_USER_ID,10             u.username,11             sa.HASH_VALUE
12         FROM v$sqlarea sa
13         LEFT JOIN all_users u
14         ON  sa.PARSING_USER_ID = u.user_id
15         WHERE sa.EXECUTIONS > 0
16         ORDER BY (sa.ELAPSED_TIME / sa.EXECUTIONS) DESC)
17 WHERE rownum <= 50;