select to_char(FORCE_MATCHING_SIGNATURE), count(1)

  from v$sql

 where FORCE_MATCHING_SIGNATURE > 0

   and FORCE_MATCHING_SIGNATURE != EXACT_MATCHING_SIGNATURE

 group by FORCE_MATCHING_SIGNATURE

having count(1) > &a

 order by 2 desc;

参考maclean文章: 利用FORCE_MATCHING_SIGNATURE捕获非绑定变量SQL

http://www.askmaclean.com/archives/%E5%88%A9%E7%94%A8force_matching_signature%E6%8D%95%E8%8E%B7%E9%9D%9E%E7%BB%91%E5%AE%9A%E5%8F%98%E9%87%8Fsql.html