oracle数据文件自动扩展与表收缩

如：现有一张表名为trojans，其中others字段很多是重复的，

删除重复的记录语句如下：

delete trojans from trojans , (select id from trojans GROUP by others having count(*)>1) as t2 where t2.id=trojans.id

这个语句一次只能删除重复中的一条记录，所以如果有n个重复记录就要执行n-1遍

多字段分组

delete pcap from pcap ,(select id from pcap group by createdtime,horse,horseprot,horseregion having count(*) >1)as p2 where p2.id=pcap.id