例子1：
delete from table1 a where exists (select 1 from table2 b where a.id=b.id)
例子2：
rebatepolicy表是主表，rebatepolicyitems是从表，从表有主表的主键，现在对于主表一些条件的数据的对应子表要求删除。
如下方式:
delete from rebatepolicyitems rs where exists ( select 1 from rebatepolicy r where rs.rebateguid=r.rebateguid and to_char(r.createdate,‘yyyyMMdd‘)=‘20161219‘ and r.creator=‘名字‘ )
delete from table1 a where exists (select 1 from table2 b where a.id=b.id)
Oracle Delete inner的方式，级联删除子表的数据方式。
原文：http://www.cnblogs.com/alsf/p/6200924.html