$sql = <<<SQLSTR
SELECT `pt`.* FROM `product_table` AS `pt`
INNER JOIN `category_table` AS `ct` ON `ct`.`category_id` = `pt`.`category_id`
WHERE `ct`.`alias` = :alias
SQLSTR;
$resultArray = Yii::$app->db->createCommand($sql)->bindValues([':alias'=>$alias])->queryAll();
$resultProductList = Product::findBySql($sql,[':alias' => $alias])->all();