Oracle Delete inner的方式，级联删除子表的数据方式。

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)