求一sql如何把数据库的空值过虑掉

[alisafan123]

select EMP_MAIL_ADDR from OC_EMPLOYEE

NULL
NULL
NULL
NULL
NULL
[e-mail]
NULL
[e-mail]
NULL

[e-mail]
[e-mail]
NULL
NULL
NULL
NULL
NULL
NULL
NULL
NULL
NULL

NULL
NULL
NULL
NULL
NULL
NULL
NULL
NULL
NULL
NULL
NULL
[e-mail]
[e-mail]
NULL
[e-mail]
NULL
NULL
NULL
[e-mail]
NULL
NULL
NULL
NULL

NULL
NULL
NULL
NULL
NULL
[e-mail]
[e-mail]

NULL
NULL
[e-mail]
[e-mail]
NULL

NULL
NULL
怎样在查询时就把空的给去掉啊，只剩下有数据的？？

[中国风]

isnull(col,'')

[dawugui]

where is not null

[中国风]

EMP_MAIL_ADDR=isnull(EMP_MAIL_ADDR,'')

[sdxiong]

select EMP_MAIL_ADDR from OC_EMPLOYEE where EMP_MAIL_ADDR is not null

[dawugui]

select EMP_MAIL_ADDR from OC_EMPLOYEE where EMP_MAIL_ADDR is not null

[wzy_love_sly]

select EMP_MAIL_ADDR from OC_EMPLOYEE
where isnull(EMP_MAIL_ADDR,'')<>''

[中国风]

條件時可:
where isnull(EMP_MAIL_ADDR,'')>''

[arrow_gx]

select EMP_MAIL_ADDR from OC_EMPLOYEE  where EMP_MAIL_ADDR is not null

[panfeifeibs]

select EMP_MAIL_ADDR from OC_EMPLOYEE where EMP_MAIL_ADDR is not null

[utpcb]

select EMP_MAIL_ADDR from OC_EMPLOYEE where EMP_MAIL_ADDR is not null

[lff642]

--参考：
select EMP_MAIL_ADDR from OC_EMPLOYEE where  isnull( EMP_MAIL_ADDR  ,'')<>''