想用isnull函数，但是select出来的不是null值

[westuser]

select col1 from tbl1 where 1=2
故意给个假条件，想查出一空行来，怎样才能使col1为null值

[alanzhou]

select * from table where id is null

[lhsxsh]

select col1 from tbl1 where col1 is null

[中国风]

select col1=isnull(null,'')--测试isnull
--------
select col1 from tbl1 where col1 is null--加上条件

[JL99000]

select null as col from tabl1
select (case when ‘条件’ then ‘值’ else null end) as col from tabl1

[hui_hui_2007]

select null as 列名

[wzy_love_sly]

declare @tb table (id int)
insert into @tb select 1
insert into @tb select 2
insert into @tb select 3

select top 1 id=null from @tb 
/*
id
NULL
*/

[windlysnowly]

select isnull(name,'null')
from table

[fcuandy]

where 1=2
这个条件恒不成立,所以取不到行,自然得不到结果集中某列为null的结果.

直接 SELECT NULL 即可.

[dawugui]

select col = case when getdate() > getdate() - 1 then 'null' end

/*
col
----
null

(1 行受影响)
*/

[dawugui]

select null col

/*
col
-----------
NULL

(1 行受影响)
*/

[wzy_love_sly]

select top 1 null from @tb

[lwl0606]

select  top 1 null as  col1   from   tbl1   where   1=1 

带from 的时候，结果集中没有符合调节的记录是不会出数据的