点击按钮，添加数据到SQL，再点击删除数据，需要php代码

<?php
// 连接数据库
$servername = "数据库服务器地址";
$username = "数据库用户名";
$password = "数据库密码";
$dbname = "数据库名";

$conn = new mysqli($servername, $username, $password, $dbname);
if ($conn->connect_error) {
    die("连接失败: " . $conn->connect_error);
}

// 添加数据
if(isset($_POST['add'])){
    $data = $_POST['data']; // 获取要添加的数据

    $sql = "INSERT INTO 表名 (列1, 列2, 列3) VALUES ('$data', 'value2', 'value3')";

    if ($conn->query($sql) === TRUE) {
        echo "数据添加成功";
    } else {
        echo "数据添加失败: " . $conn->error;
    }
}

// 删除数据
if(isset($_POST['delete'])){
    $id = $_POST['id']; // 获取要删除的数据的ID

    $sql = "DELETE FROM 表名 WHERE id = $id";

    if ($conn->query($sql) === TRUE) {
        echo "数据删除成功";
    } else {
        echo "数据删除失败: " . $conn->error;
    }
}

$conn->close();
?>

<!-- HTML 表单 -->
<form method="post" action="">
    <input type="text" name="data" placeholder="要添加的数据">
    <input type="submit" name="add" value="添加数据">
    <br>
    <input type="text" name="id" placeholder="要删除的数据的ID">
    <input type="submit" name="delete" value="删除数据">
</form>