/** * Add a group by expression to the query. * * @param string $column * @param string|null $orderMode * * @return $this The same instance to concatenate methods */ public function groupBy($column, $orderMode = null) { $columnObj = $this->factory->references('Column', $column); $orderModeObj = $orderMode ? $this->factory->references('OrderModeEnum', $orderMode) : null; $this->select->groupBy($columnObj, $orderModeObj); return $this; }