<?php

try {
    $dbh = new PDO('mysql:host=localhost;dbname=urank','root','Koji0615');

	//抽出条件（例えばusa）での件数を出す
	$sql = "SELECT count(*) FROM test02 where country = 'usa'"; 
	$result = $dbh->prepare($sql); 
	$result->execute();
//	echo (int)$result;
	$data = $result->fetch(PDO::FETCH_NUM);
	echo $data[0];

	//件数分だけUpdateする
	$i = 0;
	for($i;$i<=$data[0];$i++){		//  $data[0] が件数
			$stmt = $dbh->prepare("UPDATE test02 SET code = $i where country = :country");
			$country = 'usa';
			$stmt->bindParam(':country', $country, PDO::PARAM_STR);
			$res = $stmt->execute();
			if ($res) {
			     echo "更新完了" .$i;
			 }
			else {
			    echo "更新失敗";
			}
	}

} catch (PDOException $e) {
    var_dump($e->getMessage());
    exit;
}

?>