从数组和变量过滤时的PHP mysql查询问题

// 假设有一个搜索表单，用户可以选择不同的条件进行查询
$searchParams = array(
    'name' => 'John',
    'age' => 25,
    'city' => 'New York'
);

// 构建查询条件
$where = array();
$params = array();

if (!empty($searchParams['name'])) {
    $where[] = 'name = :name';
    $params[':name'] = $searchParams['name'];
}

if (!empty($searchParams['age'])) {
    $where[] = 'age = :age';
    $params[':age'] = $searchParams['age'];
}

if (!empty($searchParams['city'])) {
    $where[] = 'city = :city';
    $params[':city'] = $searchParams['city'];
}

// 构建SQL语句
$sql = "SELECT * FROM users";

if (!empty($where)) {
    $sql .= " WHERE " . implode(" AND ", $where);
}

// 执行查询
$stmt = $pdo->prepare($sql);
$stmt->execute($params);
$results = $stmt->fetchAll(PDO::FETCH_ASSOC);