我怎么能用laravel eloquent写这个查询

I have tables Users,departments,files and shareFiles. I want to write a query that when a user tries sending a file to another user, the share function should capture the title of the file and department of the user sending the file which would be saved in the shareFiles table.

• Users table: id, department_id
• Files table: id, title, user_id
• Department table: id, name
• ShareFiles table: title, file, department_id, user_id, sender, to

Below is what i did in the share function

public function shareFile(Request $request)
    {

        $userfile = new UserFile();
        $userfile->sender = \Auth::user()->username;
        $userfile->to = $request->user;
        $userfile->title = File::select('title')->where(['user_id' => \Auth::user()->id])
        ->orWhere('id','=','user_id')->get();

        $userfile->department = DB::table('departments')->select('departments.name')
        ->join('users','departments.id','=','users.department_id')
        ->where(['users.id' => \Auth::user()->id])
        ->get();

        $userfile->user_id = \Auth::user()->id;
        $userfile->save();
        Session::flash('message','File successfully shared !!');
        return redirect('/hr/document');
    }

Try this code:-

For title selection:

$file = File::select('title')->where(['user_id' => \Auth::user()->id]) ->orWhere('id','=','user_id')->first();

For Department:

$dept = DB::table('departments')->select('departments.name') ->join('users','departments.id','=','users.department_id') ->where(['users.id' => \Auth::user()->id]) ->first();

Note: You can also use value() and pluck() (in case if you need array of values) instead of select().