从$ _POST返回删除语句

Question

我是mysql和php的新手，我正在尝试设置一些参数来帮助我从表中删除一个条目，如果用户按下删除按钮。我目前已将其设置为用户可以使用部门，名称或课程编号搜索表格的位置。每个删除语句都是由他们使用的搜索准备的。

我遇到的问题是，当我创建我的删除语句时，我不知道如何确定SELECT语句选择的数据。下面显示了一小段代码。

if($_POST['radios'] == 0){
    $sql = "SELECT * FROM classes where department LIKE '" . $_POST['search'] . "%';";
$select = 0;
$id = $sql;//problem area. Can't figure out how to pass the needed deparment info.

if($_POST['submit'] == "delete"){
  if($select == 0){
  mysqli_query($mysqli, "DELETE FROM classes WHERE department='".$id."'"); //need $id to match the correct department from table
  mysqli_close($mysqli);
  }

编辑：表格

DROP TABLE IF EXISTS `classes`;
CREATE TABLE `classes` (
`name` varchar(255),
`department` varchar(255),
`course_id` varchar(255),
PRIMARY KEY(`course_id`),
`start` time,
`end` time,
`days` varchar(255)
);

感谢您的帮助！

Answer 1

这是删除特定“类”的一种简单方法。

Treat your buttons like a link，当您点击它时，它会重定向到特定页面，例如page.php?delete=ID。

我假设您正在动态生成表格，因此您的代码有点类似于

<?php foreach ($classes as $class) : ?>
    <tr>
        <td><?= $class->name ?></td>
        <td><?= $class->department ?></td>
        <td><?= $class->course_id ?></td>
        <td><?= $class->start ?></td>
        <td><?= $class->end ?></td>
        <td><?= $class->days ?></td>
        <!-- note the use of type="button" as we don't want to submit anything -->
        <!-- window.location.href is to redirect -->
        <td><button type="button" onclick="window.location.href='page.php?delete=<?= $class->course_id ?>'">delete</button></td>
        <td><button type="button">update</button></td>
    </tr>
<?php endforeach ?>

然后在你的处理脚本page.php中，你会做

if ($_POST['radios'] == 0){
    $sql = "SELECT * FROM classes where department LIKE '" . $_POST['search'] . "%';";
    // etc
}

// note we are using a GET method as we only did a redirection
if (!empty($_GET['delete'])) {
    $id = $_GET['delete'];
    mysqli_query($mysqli, "DELETE FROM classes WHERE course_id='".$id."'");
    mysqli_close($mysqli);
    // good idea to go back to previous page to see changes
    header('Location: previousPage.php');
    exit;
}

就是这样。

旁注：请阅读Lee Taylor关于SQL注入的评论，因为此代码容易受到攻击。开始了解prepared statements。