查询记录为空的条件怎么写

[iwkyh]

select * from t1 where dono='' 或‘null’不能得到想要的结果，就怎么写，才得查找该字段为空的值，dono为　char 15

[welyngj]

select * from t1 where dono is null

[txlicenhe]

select * from t1 where dono is null

[txlicenhe]

select * from t1 where IsNull(dono,'') = ''

[orcale]

isnull(dono,'')=''就可以了