建view表中的问题

[somesomeduo]

我有表a结构如下
id is_z b_id
-------------
1 1 1
1 0 2
1 0 3
1 1 7
1 1 8

b表结构如下
id b_desc
1 a
2 b
3 c
4 d
5 e
6 f
7 g
8 h
9 i
... ...

现在要建立view表把两张表连起来
CREATE VIEW v_a AS
SELECT
a.id,
a.is_z,
a.b_id,
b.desc
from a,b where a.b_id=b.id;

现在我增加了要求如下
当a表里is_z的值为1时，我生成view表里的b_id设值为0，并且b.desc的值设为All
请问sql语句怎么写？

[paoluo]

CREATE VIEW v_a AS
SELECT
a.id,
a.is_z,
(Case a.is_z When 1 Then 0 Else a.b_id End) As b_id,
(Case a.is_z When 1 Then 'All' Else b.[desc] End) As [desc]
from a,b where a.b_id=b.id

[somesomeduo]

!!!
3Q