Magento 2 - 在左连接中使用 group_concat 进行选择

Question

我目前正在尝试将订单产品中的 SKU 放入后端的订单网格和过滤器中。它已经在工作，但仅适用于一个 SKU，而不是订单的所有 SKU。我的控制器看起来像这样：

<?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();
    }
}

现在我的问题：是否可以将左连接中的数据选择为 group_concat？如果是这样，请给我一个关于如何做到这一点的提示。我试过这样

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

但它没有用。

Answer 1

自己解决了。缺少的是GROUP BY语句，所以我添加->group('entity_id')到查询中。我也放弃了分隔符。

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