表1如下
name code
1 A
1 B
... ...
2 A1
2 B1
2 C1
... ...得到如下表2
nc v
A A1
A B1
A C1
.. ...
B A1
B B1
B C1
.. ...
表述,表1是有二个字段为name 和 code,name值为1和2,表2意思是当表1中的name为1时nc值为 A同时把name=2的值也列出来,有点像乘积,
name code
1 A
1 B
... ...
2 A1
2 B1
2 C1
... ...得到如下表2
nc v
A A1
A B1
A C1
.. ...
B A1
B B1
B C1
.. ...
表述,表1是有二个字段为name 和 code,name值为1和2,表2意思是当表1中的name为1时nc值为 A同时把name=2的值也列出来,有点像乘积,
select a.code as nc,b.code as v
from tb a cross join tb b
where a.name = 1 and b.name = 2
from 表1 a,表1 b
where a.name = '1'
and b.name = '2'
a.code as nc,b.code as v
from
tb a cross join tb b
where
a.name = 1 and b.name = 2