laravel 5.1从与eagerloading的关系中连接多列

Question

我想使用Model :: with（relationships）方式来CONCAT多个列名（来自不同的关系）。我们如何做到这一点。

等级

id | name
1  | All

权限

id | level_id | permission_id | name 
1  | 1        | 1             | Bob Login 

用户

User::with(['level','permission'])
   ->selectRaw("CONCATE (user.name, ', ', level.name,', ',permission.name) AS uname")
   ->list('uname','id')->all();

我试过这种方式，但没有工作，我想要输出Bob Login，Admin，All

    DB::table('user AS u')
            ->join('level AS l','u.level_id','=','l.id')
            ->join('permission AS p','u.permission_id','=','p.id')
            ->selectRaw("CONCATE (user.name, ', ', level.name,', ',permission.name) AS uname")
            ->lists('uname','id');

这种方式有效，但我不想要这个

Bitmap[] contentBitmap = new Bitmap[content.size()];

for (int i = 0; i < content.size(); i++) { //content is ArrayList<String>
    String bmString = content.get(i);
    byte [] encodeByte  = Base64.decode(bmString, Base64.DEFAULT); //byte is not null
    contentBitmap[i]    = BitmapFactory.decodeByteArray(encodeByte, 0, encodeByte.length); //here I get null
}

adapter = new ViewPagerAdapter(this, contentBitmap);