运行下面的代码时出现此错误。我通常使用 msql 函数,但我试图改用 PDO。怎么了 ?
致命错误:不能在第 14 行静态调用非静态方法 PDO::query()
<?php
if(isset($_POST['username']) AND isset($_POST['password'])) {
$username = $_POST['username'];
$password = $_POST['password'];
$password_hash = md5($password);
if (!empty($username) AND !empty($password) ) {
$query = "SELECT 'id' FROM `userdatabase` WHERE 'email'='$username' AND 'password'='$password_hash'";
if($query_run = PDO::query($query)){
$query_num_rows = PDO::rowcount($query_run);
if ($query_num_rows==0){
echo 'invalid password/username';
} else {
echo 'Username/password = correct';
}
}
} else {
echo 'You must enter a password..';
}
}
?>