tsql字符串分割问题

问题如下：

某一个存储过程，过程体是：select * from atable where afield in(@str)

在外面调用的格式是:exec dbo.proc1 'a,b,c'

实现代码如下：

if object_id('dbo.fn_split')is not null drop function dbo.fn_split
go
create function dbo.fn_split 
( 
@inputstr varchar(8000), 
@seprator varchar(10) 
) 
returns @temp table (a varchar(200)) 
as 
begin 
    declare @i int 
    set @inputstr = rtrim(ltrim(@inputstr)) 
    set @i = charindex(@seprator, @inputstr) 
    while @i >= 1 
    begin 
        insert @temp values(left(@inputstr, @i - 1)) 
        set @inputstr = substring(@inputstr, @i + 1, len(@inputstr) - @i) 
        set @i = charindex(@seprator, @inputstr) 
    end 
    if @inputstr <> '\' 
        insert @temp values(@inputstr) 
    return 
end 
go 
alter PROCEDURE  dbo.Myproc1
    @str nvarchar(100)
as 
begin 
    select id,name from dbo.customer  where name in (select * from dbo.fn_split(@str,',')) 
end

exec dbo.Myproc1 '吉之岛,北京家乐福'