i changed my codes to

$titles = Titles::join('users', 'entries.user_id', '=', 'users.id')
       ->where('title_id', '0')
       ->whereIn('entries.user_id', function($query) use ($value)
            {
            $query->select(DB::raw('CASE WHEN user_id='. $value .' THEN content_id ELSE user_id END AS friendID'))
                  ->from('tasks')
                  ->where('type', 2)
                  ->where('situation', 1)
                  ->where(function ($query) use ($value) { 
                        $query->where('user_id', $value)
                              ->orWhere('content_id', $value);
                    });
            })
       ->get(['entries.*','users.name']);

       return View::make('test_home', compact('titles'));

and now i'm stucked,