商品销售管理系统 php

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

// 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);
}
echo "连接成功";
?>

<?php
// 假设商品ID为1，购买数量为5
$product_id = 1;
$quantity = 5;

// 查询当前库存
$sql = "SELECT stock FROM products WHERE id = $product_id";
$result = $conn->query($sql);
$row = $result->fetch_assoc();
$current_stock = $row['stock'];

if ($current_stock < $quantity) {
    echo "库存不足";
} else {
    // 更新库存
    $new_stock = $current_stock - $quantity;
    $update_sql = "UPDATE products SET stock = $new_stock WHERE id = $product_id";
    if ($conn->query($update_sql) === TRUE) {
        echo "购买成功";
    } else {
        echo "更新库存失败: " . $conn->error;
    }
}
?>