<?php
$db = new PDO('mysql:host=localhost;dbname=iniection', 'root', '');

$stmt = $db->prepare("SELECT * FROM user WHERE username=? AND password=?");
$stmt->execute(array($_POST['username'], $_POST['password']));


$rows = $stmt->fetchAll(PDO::FETCH_ASSOC);
$num=$stmt->rowCount();

if($num>0){
    foreach ($rows as $row){
        echo "<br>id: ".$row['id']."<br>username: ".$row['username']. "<br>password:".$row['password'];

    }
}
else echo "Not found";