select top 10 orderid,
stuff((select ','+product_no from orderdetail where o.orderid=orderid
group by orderid,product_no for xml path('')),1,1,'')
from orderdetail o group by orderid
select top 10 orderid,
stuff((select ','+product_no from orderdetail where o.orderid=orderid
group by orderid,product_no for xml path('')),1,1,'')
from orderdetail o group by orderid