How to order by using appended attribute in Laravel

问题

I created an appends attribute in Laravel Model, from the code below.

    protected $appends = array('total'=>'');

And I set the returned value.

    public function getTotalAttribute(){
           return ProductPart::where('product_id',$this->id)->count();
    }

Then I want to order records from database by using total attribute

I tried to use Product::orderBy('total','desc')->get() but it didn't work.

Does anybody has some suggestions to this?

回答1:

the orderBy takes an actual database field not an appended one

try this

$products = Product::all();
$products = $products->sortBy(function($product){
    return $product->total;
});

回答2:

If working with attributes those are not always available instantly (e.g. for freshly created models).

As expansion on Ayobami Opeyemi's answer you should be able to use Collection's sortBy if you force the attribute to evaluate by calling its function directly:

$products = Product::all();
$products = $products->sortBy(function($product){
    return $product->getTotalAttribute();
});

https://laravel.com/docs/master/collections#method-sortby

回答3:

$products = Product::all();
$products = $products->sortBy('total');

来源：https://stackoverflow.com/questions/21050476/how-to-order-by-using-appended-attribute-in-laravel