Php 尝试创建删除按钮以删除数据库中的记录

我正在做一个学校项目

这个项目的意义是我创建了一个

登录/注册表单

在那里我可以注册，登录，查看记录

但我还需要制作一个下拉菜单，因为我可以看到所有记录（用户），在它下面我需要制作一个按钮，当我选择一个记录/用户并按下删除按钮时，它需要从数据库中删除。我不知道该怎么做

这是我的代码：

<?php

---

创建一个按钮并将其命名为Delete

<a class="delete" href="delete.php?id=<?php echo $row['id']; ?>">Delete</a>

然后创建一个delete.php文件，并将这些代码放在那里

<?php include_once 'db_config_filename.php';
 // get id value
 $id = $_GET['id'];

// sql to delete a record
$sql = "DELETE FROM tablename WHERE id='$id'";

// print_r($sql);

if (mysqli_query($conn, $sql)) {
   echo "Record deleted successfully";
} 
else {
    echo "Error deleting record: " . mysqli_error($conn);
}

 //redirect here
include 'data.php';

?>

---

我几乎让它工作了。我现在有以下代码：

delete.php:

<?php

include ("connectie.php");


$sql = "SELECT * FROM users ";
$result = $conn->query($sql);

echo "<select name='user'>";
    if ($result->num_rows>0) {
    while($row = $result->fetch_assoc()) {
        echo "<option value=" . $row['username'] . ">" . $row['username'] . " 
</option>";
    }
    }
    echo "</select>";

?>


<form action="" method="GET">
<input type="hidden" name="id" value=".$row['id']." />
<input type="submit" name="delete" value="verwijderen">
</form>

<?php
    include ("deletecode.php");
?>

Deletecode.php:

<?php
$servername = "localhost";
$username = "student14_admin";
$password = "lol12345";
$dbname = "student14_jordi";

// Create connection
$conn = mysqli_connect($servername, $username, $password, $dbname);
// Check connection
if (!$conn) {
die("Connection failed: " . mysqli_connect_error());
}

// sql to delete a record
$sql = "DELETE FROM users WHERE id=3";

if (mysqli_query($conn, $sql)) {
echo "Record deleted successfully";
} else {
echo "Error deleting record: " . mysqli_error($conn);
}

mysqli_close($conn);
?>

delete.php:
Deletecode.php：

---

这只适用于记录3的课程。但现在我需要知道，如果我从下拉菜单中选择一条记录并单击删除按钮，它需要从我的数据库中删除该记录。

我现在更新了代码，我还得到了一个额外的文件，用于解决删除代码语法问题，从id=$\u GET['id']的用户处删除；还是看不到所有的代码我找不到你抱歉我不明白那我该怎么办？因为现在什么都没用了

delete.php:

<?php

include ("connectie.php");


$sql = "SELECT * FROM users ";
$result = $conn->query($sql);

echo "<select name='user'>";
    if ($result->num_rows>0) {
    while($row = $result->fetch_assoc()) {
        echo "<option value=" . $row['username'] . ">" . $row['username'] . " 
</option>";
    }
    }
    echo "</select>";

?>


<form action="" method="GET">
<input type="hidden" name="id" value=".$row['id']." />
<input type="submit" name="delete" value="verwijderen">
</form>

<?php
    include ("deletecode.php");
?>

Deletecode.php:

<?php
$servername = "localhost";
$username = "student14_admin";
$password = "lol12345";
$dbname = "student14_jordi";

// Create connection
$conn = mysqli_connect($servername, $username, $password, $dbname);
// Check connection
if (!$conn) {
die("Connection failed: " . mysqli_connect_error());
}

// sql to delete a record
$sql = "DELETE FROM users WHERE id=3";

if (mysqli_query($conn, $sql)) {
echo "Record deleted successfully";
} else {
echo "Error deleting record: " . mysqli_error($conn);
}

mysqli_close($conn);
?>