Without the table schema (I remember your previous question
], but still...) and their relations, and the specification of what you want exactly it is difficult to answer ("bind two tbls" is not even in English - despite the fact that has no meaning in sql).
Still, I have my ideas what you want. Try adding a subquery to your first one:
select sb.subcate_name, sum(p.qty), (select pr.p_name from product pr where pr.subcate_id = sb.subcate_id) as p_name
from subcategory sb
join product p on p.subcate_id = sb.subcate_id
where sb.cate_id = @cate_id
group by sb.subcate_name