查询mysql数据库用户密码

CREATE TABLE users (
    id INT AUTO_INCREMENT PRIMARY KEY,
    username VARCHAR(255) NOT NULL,
    password_hash CHAR(64) NOT NULL -- SHA-256哈希值长度为64
);

<?php
$servername = "localhost";
$username = "your_username";
$password = "your_password";
$dbname = "your_database";

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

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

// 用户输入
$input_username = $_POST['username'];
$input_password = $_POST['password'];

// 查询用户信息
$sql = "SELECT password_hash FROM users WHERE username = '$input_username'";
$result = $conn->query($sql);

if ($result->num_rows > 0) {
    // 获取密码哈希
    $row = $result->fetch_assoc();
    $stored_hash = $row['password_hash'];

    // 对输入的密码进行哈希处理
    $input_hash = hash('sha256', $input_password);

    // 比较哈希值
    if ($stored_hash === $input_hash) {
        echo "登录成功!";
    } else {
        echo "密码错误!";
    }
} else {
    echo "用户名不存在!";
}

$conn->close();
?>