Sample eloquent subquery using from

\App\Comment::select('comments.user_id', 'topics.id', 'topics.name')
        ->from(DB::raw("(select * from comments where removed = 0 order by id desc) as comments"))
        ->join('topics', 'comments.topic_id', 'topics.id')
        ->whereIn('topics.cat_id', $cats)
        ->where('topics.removed', false)
        ->groupBy('topics.id')
        ->limit(5)
        ->get();