PHP数据删除怎么操作_PHPMySQL数据删除语句使用方法

<?php
$servername = "localhost";
$username = "username";
$password = "password";
$dbname = "myDB";

// 创建连接
$conn = new mysqli($servername, $username, $password, $dbname);

// 检测连接
if ($conn->connect_error) {
  die("连接失败: " . $conn->connect_error);
}

// sql to delete a record
$sql = "DELETE FROM MyGuests WHERE id=3"; // 删除id为3的记录

if ($conn->query($sql) === TRUE) {
  echo "记录删除成功";
} else {
  echo "删除记录时出错: " . $conn->error;
}

$conn->close();
?>

<?php
$servername = "localhost";
$username = "username";
$password = "password";
$dbname = "myDB";

try {
    $conn = new PDO("mysql:host=$servername;dbname=$dbname", $username, $password);
    // 设置 PDO 错误模式为异常
    $conn->setAttribute(PDO::ATTR_ERRMODE, PDO::ERRMODE_EXCEPTION);

    // 预处理SQL语句
    $sql = "DELETE FROM MyGuests WHERE id=:id";
    $stmt = $conn->prepare($sql);

    // 绑定参数
    $id = $_POST['id']; // 从POST请求获取id，务必进行验证和过滤
    $stmt->bindParam(':id', $id);

    // 执行语句
    $stmt->execute();

    echo "记录删除成功";

    }
catch(PDOException $e)
    {
    echo "删除失败: " . $e->getMessage();
    }
$conn = null;
?>

<?php
// 假设已经建立了数据库连接 $conn

$id_to_delete = $_POST['id']; // 获取要删除的ID

// 开启事务，确保数据一致性
$conn->beginTransaction();

try {
    // 1. 从原始表查询要删除的数据
    $sql_select = "SELECT * FROM MyGuests WHERE id = :id";
    $stmt_select = $conn->prepare($sql_select);
    $stmt_select->bindParam(':id', $id_to_delete);
    $stmt_select->execute();
    $data_to_delete = $stmt_select->fetch(PDO::FETCH_ASSOC);

    // 2. 将数据插入到回收站表
    $sql_insert = "INSERT INTO MyGuests_deleted (firstname, lastname, email) VALUES (:firstname, :lastname, :email)"; // 根据你的表结构调整
    $stmt_insert = $conn->prepare($sql_insert);
    $stmt_insert->bindParam(':firstname', $data_to_delete['firstname']);
    $stmt_insert->bindParam(':lastname', $data_to_delete['lastname']);
    $stmt_insert->bindParam(':email', $data_to_delete['email']);
    $stmt_insert->execute();

    // 3. 从原始表删除数据
    $sql_delete = "DELETE FROM MyGuests WHERE id = :id";
    $stmt_delete = $conn->prepare($sql_delete);
    $stmt_delete->bindParam(':id', $id_to_delete);
    $stmt_delete->execute();

    // 提交事务
    $conn->commit();

    echo "数据已移动到回收站";

} catch (PDOException $e) {
    // 回滚事务
    $conn->rollBack();
    echo "删除失败: " . $e->getMessage();
}

$conn = null;
?>

<?php
// 假设已经建立了数据库连接 $conn

$id_to_delete = $_POST['id']; // 获取要删除的ID

try {
    // 更新 is_deleted 字段
    $sql_update = "UPDATE MyGuests SET is_deleted = 1 WHERE id = :id";
    $stmt_update = $conn->prepare($sql_update);
    $stmt_update->bindParam(':id', $id_to_delete);
    $stmt_update->execute();

    echo "数据已标记为删除";

} catch (PDOException $e) {
    echo "删除失败: " . $e->getMessage();
}

$conn = null;
?>

<?php
// 假设已经建立了数据库连接 $conn

$ids_to_delete = $_POST['ids']; // 获取要删除的ID数组，例如 "1,2,3"

// 将ID字符串转换为数组
$ids_array = explode(",", $ids_to_delete);

// 确保ID数组不为空
if (empty($ids_array)) {
    echo "没有要删除的ID";
    exit;
}

try {
    // 构建 IN 子句
    $placeholders = implode(',', array_fill(0, count($ids_array), '?')); // 生成 ?,?,? 占位符

    // 构建 SQL 语句
    $sql_delete = "DELETE FROM MyGuests WHERE id IN ($placeholders)";
    $stmt_delete = $conn->prepare($sql_delete);

    // 绑定参数
    for ($i = 0; $i < count($ids_array); $i++) {
        $stmt_delete->bindValue($i + 1, $ids_array[$i]);
    }

    // 执行语句
    $stmt_delete->execute();

    echo "成功删除了 " . $stmt_delete->rowCount() . " 条记录";

} catch (PDOException $e) {
    echo "删除失败: " . $e->getMessage();
}

$conn = null;
?>