mssql 如何判断text类型为空

Question

mssql 如何判断text类型为空

Answer 1

create table tb(id int , val text)
insert into tb values(1 , null)
insert into tb values(2 , 'aa')
go--原数据
select * from tb
/*
id          val      
----------- ---------
1           NULL
2           aa（所影响的行数为 2 行）
*/--查val is null的数据
select * from tb where val is null
/*
id          val         
----------- ------------
1           NULL（所影响的行数为 1 行）*/drop table tb

Answer 2

if object_id('tempdb..#')is not null drop table #
go
create table #(ID int identity,[Name] text)
insert # select 'adad'
insert # select null
insert # select ''
select * from # where [Name]is null
select * from # where cast([Name] as varchar(8000))=''
/*ID          Name                                                                                                                                                                                                     
----------- -------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------- 
2           NULL(影響 1 個資料列)ID          Name                                                                                                                                                                                                     
----------- -------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------- 
3           (影響 1 個資料列)*/