php mysql修改语句

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

// 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);
}

// 更新单条记录
$sql = "UPDATE users SET email='newemail@example.com' WHERE id=1";
if ($conn->query($sql) === TRUE) {
    echo "记录更新成功";
} else {
    echo "错误: " . $sql . "<br>" . $conn->error;
}

// 更新多条记录
$sql = "UPDATE products SET price=price*1.1 WHERE category='electronics'";
if ($conn->query($sql) === TRUE) {
    echo "多条记录更新成功";
} else {
    echo "错误: " . $sql . "<br>" . $conn->error;
}

$conn->close();
?>