SELECT  news.*
FROM    (
        SELECT  id
        FROM    news
        WHERE   cat_id= x
        ORDER BY
                id DESC
        LIMIT m, n
        ) o
JOIN    news
ON      news.id = o.id

from u in news
join n in
(
    from x in news
    where x.cat_id = 10
    orderby x.Id descending
    select x
).Skip(10).Take(20) on u.Id equals n.Id
select u