oracle收集
http://blog.chinaunix.net/uid-10697776-id-2935678.html
2、java List 排序 Collections.sort() 对 List 排序
http://www.blogjava.net/zygcs/archive/2008/01/17/176032.html
http://www.cnblogs.com/studyzy/archive/2008/08/23/1274838.html
http://blog.csdn.net/fly_way/article/details/6700588
http://blog.csdn.net/greenappple/article/details/7073349
6、SQL UNION 和 UNION ALL 操作符
http://www.w3school.com.cn/sql/sql_union.asp