PHP 复选框问题(行未被删除)

Question

我做了一个简单的HTML网页，上面有员工列表(只有两个atm(。

    <form method="post" action = "del.php">
    <table border = "1">
        <tr>
            <th>Employee Name</th>
        </tr>
        <?php
            $servername = "localhost";
            $username = "root";
            $password = "";
            $dbname = "lavoratori";
            // Create connection
            $conn = new mysqli($servername, $username, $password, $dbname);
            // Check connection
            if ($conn->connect_error) {
                die("Connection failed: " . $conn->connect_error);
            } 
            $sql = "SELECT nome, id FROM operai";
            $result = $conn->query($sql);
            if ($result->num_rows > 0) {
                // output data of each row
                while($row = $result->fetch_assoc()) {
                    echo"<tr>";
                    echo'<td><input type = "checkbox" name = checkbox[]" value = '.$row['id']."<td>".$row['nome']."</td>";
                    echo"</tr>";  
                }
                echo"</table>";
            }
            $conn->close();
        ?>
        <input type = "submit" name = "delete" id = "delete" value = "Delete Records">
    </form>

这是德尔.php

<?php
$servername = "localhost";
$username = "root";
$password = "";
$dbname = "lavoratori";
$conn = new mysqli($servername, $username, $password, $dbname);
if ($conn->connect_error) {
             die("Connection failed: " . $conn->connect_error);
} 
if(isset($_POST['delete'])){
    $chkarr = $_POST['checkbox'];
    foreach($chkarr as $id){
        $sql = "DELETE FROM operai WHERE id = .$id.";
        $result = $conn->query($sql);
    }
    header("Location: /test_purpose/home.php");
}
$conn->close();

？>

你们能告诉我发生了什么吗？我是PHP的新手。我正在尝试做的是从带有复选框的选择中删除特定的行。而且它不起作用，它将我重定向回主页，而不会明显删除任何内容。

Answer 1

这一行是错误的：

 $sql = "DELETE FROM operai WHERE id = .$id.";

替换为：

 $sql = "DELETE FROM operai WHERE id = {$id}";     

您还需要考虑SQL Injection：https://stackoverflow.com/a/60496/1403785