Anyone solution me to collect Data from mysql Database

My Mysql Data collect code is below:

    $date = date("Y-m-d");

    public function ip2_exists() {

        global $db,$date;

        $code = $db->select("imp","id",array("date"=>$date,"ip"=>$this->ip()));
        if($code->num_rows<1){
            return false;
        }
        else {
            return true;
        }
    }

It collect the current day datas. But I want to collect the last 5 days date.I am new in php. Please help someone. Thank you

via Chebli Mohamed