Mail Alert error in backend search

[dolec]

I have error when i use search in top bar:

 

in modules/ps_emailalerts/MailAlert.php (line 315)

            FROM `'._DB_PREFIX_.self::$definition['table'].'`

            WHERE `id_product` = '.(int) $id_product.' AND `id_product_attribute` = '.(int) $id_product_attribute;

        return Db::getInstance(_PS_USE_SQL_SLAVE_)->executeS($sql);