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