Magento 2 - Select with group_concat in Left Join

Question

I am currently trying to get the SKU from the products of an order into the order grid and filters in the backend. It is already working, but only for one SKU, not all SKUs of the order. My Controller looks like this:

<?php
namespace Vendor\Module\Model\ResourceModel\Order\Grid;

use Magento\Sales\Model\ResourceModel\Order\Grid\Collection as OriginalCollection;
use Magento\Framework\Data\Collection\Db\FetchStrategyInterface as FetchStrategy;
use Magento\Framework\Data\Collection\EntityFactoryInterface as EntityFactory;
use Magento\Framework\Event\ManagerInterface as EventManager;
use Psr\Log\LoggerInterface as Logger;

class Collection extends OriginalCollection
{
    protected $_authSession;
    public function __construct(
       EntityFactory $entityFactory,
       Logger $logger,
       FetchStrategy $fetchStrategy,
       EventManager $eventManager,
       \Magento\Backend\Model\Auth\Session $authSession
      )
    {        
       $this->_authSession = $authSession;
       parent::__construct($entityFactory, $logger, $fetchStrategy, $eventManager);
    }

    protected function _renderFiltersBefore() {
        $user = $this->_authSession->getUser();
        $joinTable = $this->getTable('sales_order_item');
        $this->getSelect()->joinLeft($joinTable, 'main_table.entity_id = sales_order_item.order_id', ['sku'])->group('entity_id');
        parent::_renderFiltersBefore();
    }
}

Now my Question: Is it possible to select the data in the left join as group_concat? If so, please give me a hint on how to do that. I have tried it like this

$this->getSelect()->joinLeft($joinTable, 'main_table.entity_id = sales_order_item.order_id', ['sku' => new \Zend_Db_Expr('group_concat(`sales_order_item`.sku SEPARATOR ",")')]);

but it didn't work.

score 9 · Answer 1 · answered Dec 19 '18 at 13:36

Solved it myself. What was missing was the GROUP BY statement, so I added ->group('entity_id') to the query. I also dropped the seperator.

$this->getSelect()->joinLeft($joinTable, 'main_table.entity_id = sales_order_item.order_id', ['sku' => new \Zend_Db_Expr('group_concat(`sales_order_item`.sku)')])->group('entity_id');

Magento 2 - Select with group_concat in Left Join

1 Answers1