how get only 1 value from db query laravel code example

Example 1: get single column value in laravel eloquent

Vehicle::find(3)->value('register_number');

Example 2: laravel get single column value

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