invoice()->collectForExport($this->ids, null, 'document_id'); } public function map($model): array { $document = $model->document; if (empty($document)) { return []; } $model->invoice_number = $document->document_number; return parent::map($model); } public function fields(): array { return [ 'invoice_number', 'code', 'name', 'amount', 'sort_order', ]; } }