laravel db table get one columns value

$items = DB::table('items')
             ->select('id', 'ref_code', 'name', 'price')
             ->where('ref_code','=', $request->ref_code)
             ->first();

// let's assume user_id is 5

DB::table('attendances')
  ->where('date_only', '=', $newdate)
  ->orderBy('logon','asc')
  ->pluck('user_id');  // "5"