oracle 随机选择一条记录
SELECT * FROM (SELECT * FROM t_enterprise_info order by dbms_random.value) WHERE rownum =1
oracle选择前10条记录
select * from test where rownum <=10
原文地址：http://www.cnblogs.com/xusweeter/p/5837430.html
http://soft.chinabyte.com/database/27/11420027.shtml
