PHP Learning Guide: How to Implement Site Search Function

<form method="GET" action="search.php">
  <input type="text" name="keyword" placeholder="请输入关键字">
  <input type="submit" value="搜索">
</form>

In the above example, we use the GET method to pass the keywords entered by the user as URL parameters to the search results page (search.php).

2. Processing search requests

Next, we need to process the search request in the search.php page and display the matching results to the user. First, we need to get the keyword entered by the user. You can use $_GET['keyword'] to get the value of the input field named "keyword" in the form.

<?php
$keyword = $_GET['keyword'];

// 连接数据库并查询匹配的数据
// ...
?>

3. Query database

Next, we need to connect to the database and query for matching data. In this example, we will use the MySQL database to store article data, and use the PDO extension to connect to the database, perform queries, and other operations. Before connecting to the database, you need to ensure that the PDO extension has been installed and the database connection information is configured.

<?php
$keyword = $_GET['keyword'];

// 连接数据库
$host = 'localhost';
$dbname = 'database_name';
$username = 'username';
$password = 'password';

try {
  $db = new PDO("mysql:host=$host;dbname=$dbname", $username, $password);
} catch (PDOException $e) {
  die("数据库连接失败：" . $e->getMessage());
}

// 执行查询
$query = "SELECT * FROM articles WHERE title LIKE '%$keyword%' OR content LIKE '%$keyword%'";
$result = $db->query($query);
$articles = $result->fetchAll(PDO::FETCH_ASSOC);
?>

In the above example, we used the LIKE operator to match keywords in the title and content fields. Note that the % prefix and suffix must be added to indicate that any string can be matched.

4. Display search results

Finally, we need to display the matching search results to the user. We can use a foreach loop to iterate through the $articles array and render each result into HTML output.

<?php
foreach ($articles as $article) {
  echo '<h3>' . $article['title'] . '</h3>';
  echo '<p>' . $article['content'] . '</p>';
}
?>

Through the above steps, we have completed the implementation of a simple on-site search function. Users can enter keywords to search and get matching article results.

However, this is just a basic example. Actual search functionality may require more complex algorithms and techniques to improve search accuracy and efficiency. For example, you can use word segmentation technology to handle Chinese searches, or use a full-text search engine to provide more advanced search capabilities.

I hope this article can provide some help for beginners to understand and implement the search function on the site. During the learning process, please continue to try and practice to deepen your understanding of the PHP search mechanism, and expand and optimize according to project needs. I wish you success in your PHP learning journey!