从MySQL PDO回显数组

Question

我有一些可以完美运行的MySQL代码：

<?php
include 'dbconfig.php';

$startdate = date("Y-m-d", strtotime($_GET['startdate']));
$class = ($_GET['class']);
$city = ($_GET['city']);
$coverage = ($_GET['coverage']);

$sql="SELECT day, week, month FROM pricing 
  WHERE '" . $startdate . "' between start_date AND end_date and class='" . $class . "' and city='" . $city . "' and coverage='" . $coverage . "'";
$result = mysqli_query($conn,$sql);


while($row = mysqli_fetch_array($result)) {

    $date_ranges = array(
        'day'   => $row['day'],
        'week'     => $row['week'],
        'month'     => $row['month']
    );

    mysqli_close($conn);

} 

$json = json_encode($date_ranges);
echo $json;
?>

但是我被告知要使用PDO来提高安全性，所以我将代码转换为PDO，到此为止：]

<?php
include 'dbconfig.php';

$startdate = date("Y-m-d", strtotime($_GET['startdate']));
$class = ($_GET['class']);
$city = ($_GET['city']);
$coverage = ($_GET['coverage']);

try {
    $conn = new PDO("mysql:host=$servername;dbname=$dbname", $username, $password);
    $conn->setAttribute(PDO::ATTR_ERRMODE, PDO::ERRMODE_EXCEPTION);
    $stmt = $conn->prepare("SELECT day, week, month FROM pricing 
  WHERE :startdate between start_date AND end_date and class=:class and city=:city and coverage=:coverage"); 

    $stmt->bindParam(':startdate', $startdate);
    $stmt->bindParam(':class', $class);
    $stmt->bindParam(':city', $city);
    $stmt->bindParam(':coverage', $coverage);

    $stmt->execute();

    $result = $stmt->setFetchMode(PDO::FETCH_ASSOC); 
    foreach(new TableRows(new RecursiveArrayIterator($stmt->fetchAll())) as $k=>$v) { 
        echo $v;

    }
}
catch(PDOException $e) {
    echo "Error: " . $e->getMessage();
}
$conn = null;
?>
问题所在肯定是这个：

$result = $stmt->setFetchMode(PDO::FETCH_ASSOC); 
    foreach(new TableRows(new RecursiveArrayIterator($stmt->fetchAll())) as $k=>$v) { 
        echo $v;
我正在尝试使输出看起来像这样（与第一个相同：）>
{"day":"35","week":"150","month":"650"}
有人可以告诉我如何完成此操作吗？谢谢！

我有一些可以正常运行的MySQL代码：

Answer 1

无论您找到什么教程，都需要放弃它。您正在编写的代码仍然容易受到SQL注入的影响，并且您并没有做太多改进。您只会使自己对本教程感到困惑。请查看https://phpdelusions.net/pdo以获得良好的PDO教程。

关于您编写​​的代码，您应该考虑一些更改：

Answer 2

如果您只是尝试以JSON格式输出查询结果，