mysql动态多条件查询

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

// 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);
}

// 获取用户输入的条件
$brand = $_GET['brand'] ?? '';
$price_min = $_GET['price_min'] ?? '';
$price_max = $_GET['price_max'] ?? '';

// 构建动态查询语句
$sql = "SELECT * FROM products WHERE 1=1";
$params = [];

if (!empty($brand)) {
    $sql .= " AND brand = ?";
    $params[] = $brand;
}
if (!empty($price_min)) {
    $sql .= " AND price >= ?";
    $params[] = $price_min;
}
if (!empty($price_max)) {
    $sql .= " AND price <= ?";
    $params[] = $price_max;
}

// 执行查询
$stmt = $conn->prepare($sql);
$stmt->bind_param(str_repeat('s', count($params)), ...$params);
$stmt->execute();
$result = $stmt->get_result();

// 处理结果
while ($row = $result->fetch_assoc()) {
    echo "ID: " . $row["id"]. " - Brand: " . $row["brand"]. " - Price: " . $row["price"]. "<br>";
}

$stmt->close();
$conn->close();
?>