Issue with group by laravel and sql - php

Question

Firstly I have problem which count products which are sold every day. In sql I have query
select product_name, sum(quantity) as quantity from invoice_product
join invoices on invoices.id = invoice_product.invoice_id
join products on products.id = invoice_product.product_id
where invoices.issued_at = '2019-05-16'
and products.`made_by_us` = 1
group by product_name
It show me interesting for me information but I used product_name to make group by but I should use product_id - I need show name too but I don't know how to do it.
Secondly I want to use it in Laravel so maybe someone know which is it possible to do it in Eloquent?
Thank you in advance :)

Answer 1

I would go with withCount() combined with select(DB::raw()), like this:
$products = Product::withCount(['invoices as quantity' => function ($query) {
$query->select(DB::raw('sum(quantity)'));
}])->get();
Then, you can access each quantity sum like this:
$quantity = $products->first()->quantity;

Answer 2

You would need to update your model relationships to achieve that.
Models:
InvoiceProduct Model
class InvoiceProduct extends Model
{
protected $table = 'invoice_product';
protected $guarded = [
'id',
];
}
public function invoice()
{
return $this->belongsTo('App\Invoice'); // Assuming `Invoice` Model is directly in app folder
}
public function product()
{
return $this->belongsTo('App\Product'); // Assuming `Product` Model is directly in app folder
}
Controller:
$full_query = InvoiceProduct::whereHas('invoice', function ($query) {
return $query->where('issued_at', '2019-05-16');
})->whereHas('product', function ($query) {
return $query->where('made_by_us', 1);
});
$product_names = $full_query->get(['product_name']);
$total_quantities = $full_query->sum('quantity');