sql问题,谢谢了.

lotto

TableA:
Field_A   Field_B
A           ssdf
A
C
A           sdf
B           sdfsd
C
B           sdfsf
B

我想选出Field_A在Field_B字段里所有都为空的字母. 结果也就是C. 怎么选,请教了。谢谢。

枫影谁用了

select  Field_A  from  tableA where  Field_B is null...

这样也要问？

cenalulu

select b.Field_A
from
    tbl_name  a
join
    (select count(field_B) as total ,Field_A from tbl_name where field_B is not null group by Field_A)  b
on a.Field_A = b.Field_A
where b.total=0;

枫影谁用了

喔，sorry,我看错了

renxiao2003

原帖由 cenalulu 于 2009-11-20 14:42 发表
select b.Field_A
from
    tbl_name  a
join
    (select count(field_B) as total ,Field_A from tbl_name where field_B is not null group by Field_A)  b
on a.Field_A = b.Field_A
where b.t ...

有高手在啊。

lotto

无限感激....