oracle with as 有关问题

oracle with as 问题
请高手帮忙解决下：

with a as
(select 1, 2 from dual),
b as 
(select 3, 4 from dual)
insert into dual select a.*, b.* from a, b;

报错：缺少select 关键字  

为什么？ 在线等。

[解决办法]

SQL code

--加insert into dual做什么？改下试试with a as(select 1, 2 from dual),b as  (select 3, 4 from dual)select a.*, b.* from a, b;
[解决办法]
你要insert，那你也不能insert到dual，你要写实际的表啊，还有就是字段对应了吗？
[解决办法]
SQL code
insert into dualwith a as(select 1, 2 from dual),b as  (select 3, 4 from dual)select a.*, b.* from a, b;
[解决办法]
可以向dual表 插数据吗？
[解决办法]
SQL code
insert into XXXwith a as(select 1, 2 from dual),b as  (select 3, 4 from dual)select a.*, b.* from a, b;