Artur-Salo

select p.poduct_id from products_comments p
where p.comment_id = 1
and not exists (select * from products_comments q where q.poduct_id = p.poduct_id and comment_id <> 1)
;

select kpid, count(uid)
from таблица
group by kpid
order by count(uid) desc
limit 10
;