customer_group,, ----> customer_group, (лишняя запятая)
<?xml version="1.0" encoding="utf-8"?>
<modification>
<name>CustomerGroup_to_OrderList</name>
<code>CustomerGroup_to_OrderList</code>
<version>1.0</version>
<author>Prooksius(Opencartforum)</author>
<link>CustomerGroup_to_OrderList</link>
<file path="admin/model/sale/order.php">
<operation>
<search position="replace"><![CDATA[$sql = "SELECT o.order_id, CONCAT(o.firstname, ' ', o.lastname) AS customer, (SELECT os.name FROM " . DB_PREFIX . "order_status os WHERE os.order_status_id = o.order_status_id AND os.language_id = '" . (int)$this->config->get('config_language_id') . "') AS order_status, o.shipping_code, o.total, o.currency_code, o.currency_value, o.date_added, o.date_modified FROM `" . DB_PREFIX . "order` o";]]></search>
<add><![CDATA[$sql = "SELECT o.order_id, CONCAT(o.firstname, ' ', o.lastname) AS customer,
(SELECT os.name FROM " . DB_PREFIX . "order_status os WHERE os.order_status_id = o.order_status_id
AND os.language_id = '" . (int)$this->config->get('config_language_id') . "') AS order_status,
(SELECT cgd.name FROM " . DB_PREFIX . "customer c LEFT JOIN " . DB_PREFIX . "customer_group_description cgd
ON cgd.customer_group_id = c.customer_group_id
WHERE c.customer_id = o.customer_id
AND cgd.language_id = '" . (int)$this->config->get('config_language_id') . "')
AS customer_group, o.shipping_code, o.total, o.currency_code, o.currency_value, o.date_added, o.date_modified
FROM `" . DB_PREFIX . "order` o";]]></add>
</operation>
</file>
<file path="admin/language/ru-ru/sale/order.php">
<operation>
<search><![CDATA[// Text]]></search>
<add position="after"><![CDATA[$_['column_group'] = 'Группа покупателей';]]></add>
</operation>
</file>
<file path="admin/controller/sale/order.php">
<operation>
<search><![CDATA['order_status' => $result['order_status'] ? $result['order_status'] : $this->language->get('text_missing'),]]></search>
<add position="after"><![CDATA['customer_group'=> $result['customer_group'],]]></add>
</operation>
</file>
<file path="admin/view/template/sale/order_list.twig">
<operation>
<search><![CDATA[<td class="text-left">{% if sort == 'order_status' %} <a href="{{ sort_status }}" class="{{ order|lower }}">{{ column_status }}</a> {% else %} <a href="{{ sort_status }}">{{ column_status }}</a> {% endif %}</td>]]></search>
<add position="before"><![CDATA[ <td class="text-left">{{ column_group }}</td>]]></add>
</operation>
<operation>
<search><![CDATA[<td class="text-left">{{ order.order_status }}</td>]]></search>
<add position="before"><![CDATA[<td class="left">{{ order.customer_group }}</td>]]></add>
</operation>
</file>
</modification>