UPDATE table_name SET column_name = column_name + value WHERE id = some_id;

<?php
// 连接到 MySQL 数据库
$conn = mysqli_connect("localhost", "username", "password", "database_name");

// 检查连接是否成功
if (!$conn) {
    die("Connection failed: " . mysqli_connect_error());
}

// 更新数据
$sql = "UPDATE table_name SET column_name = column_name + ? WHERE id = ?";
$stmt = $conn->prepare($sql);
$stmt->bind_param("ii", $value, $some_id);
$stmt->execute();

// 关闭连接和语句句柄
$stmt->close();
$conn->close();
?>