Select SUM from subquery while using whereHas in Laravel

Question

I have 2 tables, customers and customer_invoices, and I want to get all the customers with a condition on their invoices, and select specific columns (

Answer 1

You can use withCount() to get sum from related model as

$result = Customer::select([
            'customers.id',
            'customers.last_name'
        ])->withCount([
            'customerInvoices as invoice_sum' => function($query) {
                $query->select(DB::raw('SUM(total_price)'));
            }
        ])->whereHas('customerInvoices', function(Builder $q) {
            $q->where('customer_invoices.status', 1);
        })->get();

Another approach to get sum, you can define a hasOne() relation in your Customer model like

public function invoice_sum()
{
    return $this->hasOne(CustomerInvoice::class)
        ->select('customer_id',
            DB::raw('sum(total_price)')
        )->groupBy('customer_id');
}

And in query builder

$result = Customer::select([
            'customers.id',
            'customers.last_name',
        ])->with('invoice_sum')
          ->whereHas('customerInvoices', function(Builder $q) {
            $q->where('customer_invoices.status', 1);
        })->get();      

As per Eloquent : withCount() overrides the $columns on get() issue first put select() mehtod and then use with() function