1. 数据库查询
使用 SQL 语句对商品数据进行排序：
sql
-- 按销量降序
SELECT * FROM products ORDER BY sales DESC;
-- 按销量升序
SELECT * FROM products ORDER BY sales ASC;
-- 按价格降序
SELECT * FROM products ORDER BY price DESC;
-- 按价格升序
SELECT * FROM products ORDER BY price ASC;
2. PHP 代码
在 PHP 中执行 SQL 查询，并返回 JSON 数据：
php
<?php
$pdo = new PDO("mysql:host=localhost;dbname=shop", "root", "password");
$sort_by = $_GET['sort_by'] ?? 'sales'; // 默认按销量排序
$sort_order = $_GET['sort_order'] ?? 'DESC'; // 默认降序
$sql = "SELECT * FROM products ORDER BY $sort_by $sort_order";
$result = $pdo->query($sql);
$products = $result->fetchAll(PDO::FETCH_ASSOC);
echo json_encode($products);
?>
