Sql function 多行中的列合并为一行一列的方法

CREATE TABLE tb(standards varchar(50), amount varchar(50), variation varchar(50),statuss varchar(50),Reason varchar(50))
insert into tb values(55,279,4,物量积压,加工人员设备不足;T排制作进度较慢;)
insert into tb values(55,279,4,物量积压,部件人员不足;)
insert into tb values(55,279,4,物量积压,跨间场地积压;图纸问题较多;)
insert into tb values(56,300,4,物量积压,AAAA;)
insert into tb values(56,300,4,物量积压,BBBB;)
insert into tb values(56,300,4,物量积压,CCCC;)

create function test(@standards varchar(100))
returns varchar(8000)
as
begin
declare @re varchar(500)
set @re =
select @re = @re+,+Reason
from tb
where @standards=standards
return (stuff(@re,1,1,))
end

select distinct standards,amount,variation,statuss,Reason = dbo.test(55) from tb where standards=55
select distinct standards,amount,variation,statuss,Reason = dbo.test(56) from tb where standards=56