PHP Developer City를 사용하여 매장 평가 통계 기능을 구현하는 방법

function getShopRatings($shop_id) {
    // 连接数据库
    $conn = new mysqli("localhost", "username", "password", "shop_rating");
    
    // 查询商家的所有评价信息
    $sql = "SELECT * FROM rating WHERE shop_id = '$shop_id'";
    $result = $conn->query($sql);
    
    // 返回评价信息数组
    $ratings = array();
    while ($row = $result->fetch_assoc()) {
        $ratings[] = $row;
    }
    
    return $ratings;
}

function calculateShopRating($shop_id) {
    $ratings = getShopRatings($shop_id);
    
    // 计算商家评分的平均值
    $total_rating = 0;
    foreach ($ratings as $rating) {
        $total_rating += $rating['rating'];
    }
    $avg_rating = $total_rating / count($ratings);
    
    return $avg_rating;
}

$shop_id = $_GET['shop_id'];
$avg_rating = calculateShopRating($shop_id);

echo "店铺评分：$avg_rating";

function addShopRating($shop_id, $rating, $comment) {
    // 连接数据库
    $conn = new mysqli("localhost", "username", "password", "shop_rating");
    
    // 插入评价信息
    $sql = "INSERT INTO rating (shop_id, rating, comment, timestamp) VALUES ('$shop_id', '$rating', '$comment', NOW())";
    $conn->query($sql);
    
    // 返回插入成功的评价ID
    return $conn->insert_id;
}

<form action="submit_rating.php" method="post">
    <input type="hidden" name="shop_id" value="<?php echo $shop_id; ?>">
    <label for="rating">评分：</label>
    <select name="rating" id="rating">
        <option value="1">1星</option>
        <option value="2">2星</option>
        <option value="3">3星</option>
        <option value="4">4星</option>
        <option value="5">5星</option>
    </select>
    <br>
    <label for="comment">评论：</label>
    <textarea name="comment" id="comment" rows="5"></textarea>
    <br>
    <input type="submit" value="提交评价">
</form>