源：http://bbs.csdn.net/topics/220057226

create function dbo.EAN_13(@value varchar(13))
returns varchar(13)
as
begin
declare @s1 int ,@s2 int

declare @t table (id int identity(1,1),b bit)

insert into @t(b)
select top 13 1 from syscolumns

set @value=http://www.mamicode.com/‘0‘+reverse(@value)

select @s1=sum(cast(substring(@value,id,1) as int))
from @t a
where len(@value)>=id and id%2=0

set @s1=@s1*3

select @s2=sum(cast(substring(@value,id,1) as int))
from @t a
where len(@value)>=id and id>=3 and id%2=1

set @s1=@s1+@s2
return left(reverse(@value),12)+ltrim(10-len(@s1))
end
go

select dbo.EAN_13(‘234235654652‘) ean13
go

drop function EAN_13

/*
ean13
-------------
2342356546528

（所影响的行数为 1 行）
*/

(转)基于SQL的EAN-13条形码校验位生成