yii\sphinx\QueryBuilder::buildOrderBy PHP Method

    public function buildOrderBy($columns)
    {
        if (empty($columns)) {
            return '';
        }
        $orders = [];
        foreach ($columns as $name => $direction) {
            if ($direction instanceof Expression) {
                $orders[] = $direction->expression;
            } else {
                $orders[] = $this->db->quoteColumnName($name) . ($direction === SORT_DESC ? ' DESC' : ' ASC');
            }
        }
        return 'ORDER BY ' . implode(', ', $orders);
    }