[8.x] Add loadAggregate() and load[min(), max(), sum() & avg()] methods to …

[khalilst]

This PR adds the following methods to the Eloquent/{Collection, Model} which were missing in PR #34965:

    //Eloquent/Collection

    public function loadAggregate($relations, $column, $function = null) {...}
    public function loadCount($relations) {...} //Just modified.
    public function loadMax($relations, $column)  {...}
    public function loadMin($relations, $column)  {...}
    public function loadSum($relations, $column)  {...}
    public function loadAvg($relations, $column)  {...}

And

    //Eloquent/Model

    public function loadAggregate($relations, $column, $function = null) {...}
    public function loadCount($relations) {...} //Just modified.
    public function loadMax($relations, $column) {...}
    public function loadMin($relations, $column) {...}
    public function loadSum($relations, $column) {...}
    public function loadAvg($relations, $column) {...}

    public function loadMorphAggregate($relation, $relations, $column, $function = null) {...}
    public function loadMorphCount($relation, $relations) {...} //Just modified.
    public function loadMorphMax($relation, $relations, $column) {...}
    public function loadMorphMin($relation, $relations, $column) {...}
    public function loadMorphSum($relation, $relations, $column) {...}
    public function loadMorphAvg($relation, $relations, $column) {...}

[dbakan]

Will it be possible to load multiple relations at once? Maybe even with constraints? Such as:

$orders->loadSum([
   'orderItems.price as original_total_cost',
   'orderItems.weight as shipping_weight',
   'orderItems.price as total_refunded' => function($query) { 
      $query->where('is_refunded', true);
   },
])

[khalilst]

@dbakan Yes, it is possible. Just you forgot to specify the second argument (the $column).

[dbakan]

@khalilst I specified different columns intentionally as part of the array keys/relation names:
orderItems.price vs orderItems.weight.

To me, this would be closer to the "Laravel Way", esp. if all aggregates are being fetched within a single statement.

[khalilst]

@dbakan It needs to change the source withAggregate() method in QueriesRelationships and I think it is a good idea to apply those changes in another PR after confirmation by @taylorotwell .

[dbakan]

@khalilst I'd be happy to help with those changes.

[dbakan]

@khalilst This is an approach I've been working on lately: https://github.com/dbakan/aggregate

It does not work for the current 8.x, but it does work for v8.11.2 (before the new withSum() etc. was merged).

It supports the dot syntax, mixed constraints and some more. It's still work in progress and has some issues, but personally, I prefer:

Order::withSum('products.price as total');
// over
Order::withSum('products as total', 'price');

And I think this would be more flexible, e.g. mix aggregates:

Order::withAggregate([
    'products as products_count' => 'count',
    'products.deleted_at AS deleted_count' => 'count',
    'products.quantity as total_items' => 'sum', // using sum() here now!
    'products.price as special_aggregate' => function($query) {
        // write more complex aggregates:
        $query->select(\DB::raw('SUM(product_orders.quantity*product_orders.price)'));
    },
    'products.discount' => 'MAX',
    'products.quantity as quantity_list' => 'group_concat', // (I am working on JSON_ARRAY_AGGR too)
]);

What do you think @khalilst @taylorotwell ?

[khalilst]

@dbakan I disagree with all respect.
IMO, it pushes towards Raw SQL, instead of PHP.

If I was there to make withCount(), I prefer to use this:

Model::withCount($relations, $alias)

instead of

Medel::withCount('relation as alias');

But if others and @taylorotwell have your idea I will make another PR for these changes with your help.

[dbakan]

IMO, it pushes towards Raw SQL, instead of PHP.

@khalilst Yes, this may be true.

I just liked the idea of supporting multiple aggregates over different columns like:

Model::loadSum(
   'relation.price AS total_cost', 
   'relation.weight AS total_weight', 
   ...
);

And doing it in a single query just like withCount. But maybe it's just me.