Question

我需要一些帮助来弄清楚这个的逻辑，因为在我看到的大多数教程中，他们只需要在数据库中存储topics_count int，并且每次在该特定论坛中创建主题时他们都会增加topics_count为他们创建的论坛+1;

但我们是否可以通过使用mysqli_num_rows获取值来实现此目的？这将返回与论坛相关的总行数（主题）。但问题是当论坛在数组中时，我怎样才能创建这种关系。

论坛和主题都有：

ID
标题
描述

我知道安全问题。这个例子只是一种做法。

这就是我如何从数据库中显示论坛并将href回显到每个论坛。

                $array_forums = mysqli_fetch_assoc($res_forums); 
                    echo "<div id='forum_{$array_forums["forum_id"]}' class='forum_classic'>";
                        echo "<div id='forum_classic_status'></div>";                           
                        echo "<div id='forum_classic_container'>";
                            echo "<div id='forum_classic_icon'></div>";
                            echo "<div id='forum_classic_description'>";
                                    echo "<a href=forum.php?forum=" . urlencode($array_forums["forum_id"]) . ">";
                                        echo "<h1>{$array_forums["forum_title"]}</h1>";
                                    echo "</a>";
                                echo "<p>{$array_forums["forum_description"]}</p>";
                            echo "</div>";
                        echo "</div>";
                        echo "<div id='forum_classic_topics'>Topics</div>";
                        echo "<div id='forum_classic_replies'>Replies</div>";
                        echo "<div id='forum_classic_lastposter'>Lastposter</div>";
                    echo "</div>";
                }

这是我在点击链接后在每个论坛中显示主题的方式。

            $forum_id = $_GET['forum'];

            //1. Perform database query for topics
            $sql_topic = "SELECT * FROM topics WHERE topic_forum_id = {$forum_id}";
            $res_topic = mysqli_query($conn, $sql_topic);
            //2. Display returned data from topics
            if (mysqli_num_rows($res_topic) >= 1) {
                $array_topic = mysqli_fetch_assoc($res_topic);
                echo "<div id='topic_{$array_topic["topic_id"]}'>{$array_topic["topic_title"]}";
                echo "</div>";
            } else {
                echo "<a href='community.php'>Return To Forum Index</a>";
                echo "<p>There are no topics in this forum yet.</p>";
            }

Answer 1

您可以使用count来计算行数

$sql_topic = "SELECT count(*) FROM topics WHERE topic_forum_id = {$forum_id}";
$row = mysqli_fetch_row($sql_topic);
$num = $row[0];

$ num将返回特定论坛

中的主题数量

Answer 2

在@Anil Shrestha的帮助下，$ num将作为主题计数器。

                    $sql_topic = "SELECT count(*) FROM topics WHERE topic_forum_id = {$array_forums["forum_id"]}";
                    $res_topic = mysqli_query($conn, $sql_topic);
                    $row = mysqli_fetch_row($res_topic);
                    $num = $row[0];

计算与论坛相关的总帖子 - PHP Logic

2 个答案: