Detailed code explanation of how to implement advanced search functions in PHP

In web development, advanced search functions are very common. Many websites provide advanced search functions, allowing users to more precisely query the information they want. In this article, we will discuss how to implement advanced search functionality using PHP.

1. Understand the advanced search function

Search is one of the most important functions on the website. Most websites offer a basic search box that lets users enter their keywords in order to search for relevant content. However, there are situations where a basic search box doesn't meet the user's needs. For example, when users want to search for specific content using multiple criteria, a basic search box is not enough. At this time, you need to use the advanced search function.

The advanced search feature allows users to narrow their search by entering multiple criteria. For example, an e-commerce website may provide advanced search capabilities to allow users to search for products by brand, price, color, etc. To implement advanced search functionality, we need to design a form that allows users to enter multiple criteria, and then write code to retrieve relevant data from the database.

2. Write an advanced search form

In order to implement the advanced search function, we need to create a form with multiple input fields. These input fields should allow users to enter various criteria they want to search for, such as price range, color, size, etc. Here is a sample advanced search form:

<form method="get" action="search.php">
    <label for="keywords">关键字：</label>
    <input type="text" id="keywords" name="keywords"><br>

    <label for="category">类别：</label>
    <select id="category" name="category">
        <option value="">请选择</option>
        <option value="books">书籍</option>
        <option value="electronics">电子产品</option>
        <<option value="clothing">服装</option>
    </select><br>

    <label for="price_min">最低价：</label>
    <input type="text" id="price_min" name="price_min"><br>

    <label for="price_max">最高价：</label>
    <input type="text" id="price_max" name="price_max"><br>

    <label for="color">颜色：</label>
    <input type="text" id="color" name="color"><br>

    <label for="size">尺码：</label>
    <input type="text" id="size" name="size"><br>

    <input type="submit" value="搜索">
</form>

In this form, we have included the following fields:

1. Keywords: Allows the user to enter the keywords they want to search for.
2. Category: Allows users to search by category.
3. Lowest Price and Highest Price: Allow users to enter the lowest and highest prices to search for matching products.
4. Color and Size: Allows users to search by color and size.
5. Search button: When the user clicks this button, the form will be submitted and the search operation will be performed.

This is just a simple form example, you can customize the form fields according to your needs.

3. Processing the submission of the advanced search form

Once the user submits the advanced search form, we need to collect the conditions entered by the user and then use them to retrieve relevant data in the database. Here is sample PHP code to handle submission of an advanced search form:

<?php
// 连接数据库
$conn = mysqli_connect("localhost", "username", "password", "database");

// 检查连接是否成功
if (mysqli_connect_errno()) {
    echo "连接 MySQL 失败：" . mysqli_connect_error();
    exit;
}

// 从$_GET数组中收集用户输入的条件
$keywords = isset($_GET["keywords"]) ? $_GET["keywords"] : "";
$category = isset($_GET["category"]) ? $_GET["category"] : "";
$price_min = isset($_GET["price_min"]) ? $_GET["price_min"] : "";
$price_max = isset($_GET["price_max"]) ? $_GET["price_max"] : "";
$color = isset($_GET["color"]) ? $_GET["color"] : "";
$size = isset($_GET["size"]) ? $_GET["size"] : "";

// 构造SQL查询语句
$sql = "SELECT * FROM products WHERE 1=1";

if (!empty($keywords)) {
    $sql .= " AND (name LIKE &#39;%{$keywords}%&#39; OR description LIKE &#39;%{$keywords}%&#39;)";
}

if (!empty($category)) {
    $sql .= " AND category=&#39;{$category}&#39;";
}

if (!empty($price_min) && !empty($price_max)) {
    $sql .= " AND price >= {$price_min} AND price <= {$price_max}";
}

if (!empty($color)) {
    $sql .= " AND color='{$color}'";
}

if (!empty($size)) {
    $sql .= " AND size='{$size}'";
}

// 执行查询
$result = mysqli_query($conn, $sql);

// 处理查询结果
if (!$result) {
    echo "查询数据库失败：" . mysqli_error($conn);
    exit;
}

while ($row = mysqli_fetch_assoc($result)) {
    echo "{$row['name']} - {$row['description']} - {$row['category']} - {$row['price']} - {$row['color']} - {$row['size']}<br>";
}

mysqli_close($conn);
?>

In this PHP code snippet, we do the following:

1. Connect to the database.
2. Collect user-entered conditions from the $_GET array.
3. Use conditions to construct SQL query statements.
4. Execute the query and process the results.

We use 1=1 as the starting point of the WHERE clause because it saves us from having to deal with the first condition manually. We then build the query by checking whether each condition exists. If the condition exists, it is added to the query statement. Finally, we execute the query and loop through the results.

4. Summary

In this article, we discussed how to use PHP to implement advanced search functionality. To implement advanced search functionality, we need to design a form with multiple input fields and use PHP to retrieve relevant data from the database. Although only the basic implementation is shown in this article, you can customize this functionality to suit your needs. I hope this article helps you implement your own advanced search capabilities.

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