php实现网站查询功能实现
数据库连接与查询准备
使用PHP的PDO或MySQLi扩展连接数据库。PDO支持多种数据库，MySQLi专为MySQL设计。以下是PDO连接示例：
$host = 'localhost';
$dbname = 'your_database';
$username = 'your_username';
$password = 'your_password';
try {
$pdo = new PDO("mysql:host=$host;dbname=$dbname", $username, $password);
$pdo->setAttribute(PDO::ATTR_ERRMODE, PDO::ERRMODE_EXCEPTION);
} catch (PDOException $e) {
die("Connection failed: " . $e->getMessage());
}表单设计与数据接收
创建HTML表单用于用户输入查询条件。表单需使用GET或POST方法提交数据：
<form method="GET" action="search.php">
<input type="text" name="search_term" placeholder="Enter search term">
<button type="submit">Search</button>
</form>在PHP中接收并过滤用户输入，防止SQL注入：
$searchTerm = isset($_GET['search_term']) ? trim($_GET['search_term']) : '';
$searchTerm = htmlspecialchars($searchTerm, ENT_QUOTES, 'UTF-8');执行SQL查询
使用预处理语句执行查询，确保安全性。假设查询products表中匹配名称或描述的内容：
if (!empty($searchTerm)) {
$stmt = $pdo->prepare("SELECT * FROM products
WHERE name LIKE :search OR description LIKE :search");
$searchParam = "%$searchTerm%";
$stmt->bindParam(':search', $searchParam, PDO::PARAM_STR);
$stmt->execute();
$results = $stmt->fetchAll(PDO::FETCH_ASSOC);
}结果显示与分页处理
遍历查询结果并显示。添加基础分页功能：
if (!empty($results)) {
foreach ($results as $row) {
echo "<div class='result-item'>";
echo "<h3>" . htmlspecialchars($row['name']) . "</h3>";
echo "<p>" . htmlspecialchars($row['description']) . "</p>";
echo "</div>";
}
} else {
echo "<p>No results found.</p>";
}分页实现示例：
$perPage = 10;
$page = isset($_GET['page']) ? (int)$_GET['page'] : 1;
$offset = ($page - 1) * $perPage;
$totalQuery = $pdo->query("SELECT COUNT(*) FROM products
WHERE name LIKE '%$searchTerm%'")->fetchColumn();
$totalPages = ceil($totalQuery / $perPage);高级搜索功能扩展
添加多条件筛选，如价格范围、分类等：
<input type="number" name="min_price" placeholder="Min price">
<input type="number" name="max_price" placeholder="Max price">
<select name="category">
<option value="">All Categories</option>
<option value="electronics">Electronics</option>
</select>对应PHP处理：
$conditions = [];
$params = [];
if (!empty($searchTerm)) {
$conditions[] = "(name LIKE :search OR description LIKE :search)";
$params[':search'] = "%$searchTerm%";
}
if (!empty($_GET['min_price'])) {
$conditions[] = "price >= :min_price";
$params[':min_price'] = (float)$_GET['min_price'];
}
// 类似处理其他条件...
$query = "SELECT * FROM products";
if (!empty($conditions)) {
$query .= " WHERE " . implode(" AND ", $conditions);
}
$stmt = $pdo->prepare($query);
foreach ($params as $key => &$val) {
$stmt->bindParam($key, $val);
}性能优化建议
为常用搜索字段添加数据库索引：
CREATE INDEX idx_product_name ON products(name);
CREATE INDEX idx_product_price ON products(price);考虑使用全文检索提高文本搜索效率：
ALTER TABLE products ADD FULLTEXT(name, description);
SELECT * FROM products WHERE MATCH(name, description) AGAINST(:search IN BOOLEAN MODE);
