Sum (quantity * price)

public function items()
    {
        return $this->hasMany(OrderItem::class);
    }

Forms\Components\Placeholder::make('total')
->content(fn ($record) => $record->items->sum(\DB::raw('quantity * price')))

public function items()
    {
        return $this->hasMany(OrderItem::class);
    }

Forms\Components\Placeholder::make('total')
->content(fn ($record) => $record->items->sum(\DB::raw('quantity * price')))

  public function getTotalAttribute()
  {
    return $this->quantity * $this->price;
  }

Forms\Components\Placeholder::make('total')
->content(fn ($record) => $record->items->total)

  public function getTotalAttribute()
  {
    return $this->quantity * $this->price;
  }

Forms\Components\Placeholder::make('total')
->content(fn ($record) => $record->items->total)