Question

我是Php的新手，我得到了这段代码，如果没有关于所选类别的帖子，我想要显示警告信息。我试过＆＃34; mysqli_num_row＆＃34;但我没有工作。谢谢你从现在开始:)）

 <?php
                        if(isset($_GET['category'])){
                            $post_category_id = $_GET['category'];
                        }

                        $query = "SELECT * FROM posts WHERE post_category_id = $post_category_id ";
                        $select_all_posts_query = mysqli_query($connection, $query);
                        $num_rows = mysqli_num_rows($select_all_posts_query);

                        if($num_rows.count() < 0){
                                echo "<h1 class='text-center'>THERE IS NO POST ABOUT THIS CATEGORY!</h1>";
                                echo "<img style='margin-left:225px;' width='300' class='img-responsive' src='images/sorry.png'/>";
                        }else{
                        while($row = mysqli_fetch_assoc($select_all_posts_query)){
                            $post_id = $row['post_id'];
                            $post_title = $row['post_title'];
                            $post_author = $row['post_author'];
                            $post_date = $row['post_date'];
                            $post_image = $row['post_image'];
                            $post_content = substr($row['post_content'], 0, 50);           
                            ?>
                        <h1 class="page-header">
                Page Heading
                <small>Secondary Text</small>
            </h1>
                        <!-- First Blog Post -->
                        <h2>
                <a href="post.php?p_id=<?php echo $post_id; ?> "><?php echo $post_title ?></a>
            </h2>
                        <p class="lead">
                            by
                            <a href="index.php">
                                <?php echo $post_author ?>
                            </a>
                        </p>
                        <p><span class="glyphicon glyphicon-time"></span>
                            <?php echo $post_date ?>
                        </p>
                        <hr>
                        <a href="post.php?p_id=<?php echo $post_id; ?>"><img width="600" class="img-responsive" src="images/<?php echo $post_image;?>" alt=""></a>
                        <hr>
                        <p>
                            <?php echo $post_content ?>
                        </p>
                        <a class="btn btn-primary" href="#">Read More <span class="glyphicon glyphicon-chevron-right"></span></a>
                        <hr>
                        <?php } }?>

这些都是我的代码。

Answer 1

mysqli_num_rows - 返回结果集中的行数。

无需使用$num_rows.count()

使用：

if($num_rows <= 0){

    echo "<h1 class='text-center'>THERE IS NO POST ABOUT THIS CATEGORY!</h1>";
    echo "<img style='margin-left:225px;' width='300' class='img-responsive' src='images/sorry.png'/>";

Answer 2

不知道它是什么

if($num_rows.count() < 0){

但您已经在使用mysqli_num_rows()，所以只需将上面提到的行替换为：

if($num_rows <= 0){

Answer 3

或者为了保存不必要的变量赋值，你可以这样做

注意我使用<=小于或等于而不只是<如果查询没有返回结果，则它将为零，而不是小于零。

if(mysqli_num_rows($select_all_posts_query) <= 0){
   echo "<h1 class='text-center'>THERE IS NO POST ABOUT THIS CATEGORY!</h1>";
   echo "<img style='margin-left:225px;' width='300' class='img-responsive' src='images/sorry.png'/>";
}else{

我怎样才能使用＆＃34; mysqli_num_rows＆＃34;在PHP？

3 个答案: