Question

我目前有一个查询集，用于选择与特定帖子相关联的评论。我还需要选择针对该帖子提交评论的用户详细信息。我在这里苦苦挣扎，需要一些建议。

这是我当前的查询：

    $q = "SELECT p.post_id, f.created_date, f.comment_id, f.comment_content, j.id 
             FROM forum_post AS p
             INNER JOIN comment_post_join AS j ON p.post_id = j.post_id
             INNER JOIN forum_comment AS f ON f.comment_id = j.comment_id
             WHERE p.post_id = '$id'
             ORDER BY created_date ASC
         ";   

    $r = mysqli_query ($dbc, $q); // Run the query.


    // FETCH AND PRINT ALL THE RECORDS
    while ($row = mysqli_fetch_array($r)) {

    echo '
    <div style="border-bottom: thin solid #ddd;">
        <p style="font-size: 13px;">'.$row["comment_content"] . '</p><p style="font-size: 12px;">' .date("F j, Y, g:i a", strtotime($row["created_date"])). '</p>
    </div>
    ';

}

正如您所看到的，我正在从forum_post表中选择，因为这是我的帖子所在的位置。我使用inner_join来引用帖子及其相关评论，但我还需要从用户那里获取详细信息，因为我还有另一个表user_comment_join，在提交评论时也会更新创建行的表，并提交用户ID和注释ID。

我对实际帖子做了类似的事情并通过这样做引用用户：

    $q = "SELECT u.user_id, u.first_name, u.last_name, f.post_created, f.post_id, f.post_title, f.post_content, j.id 
             FROM users AS u
             INNER JOIN user_post_join AS j ON u.user_id = j.user_id
             INNER JOIN forum_post AS f ON f.post_id = j.post_id
             WHERE f.post_id = '$id'
         ";

我希望我在这里解释了我的问题，任何建议都会很棒。

我自己也是这样尝试过......：

    $q = "SELECT p.post_id, f.created_date, f.comment_id, f.comment_content, u.user_id, u.first_name, u.last_name, j.id 
             FROM forum_post AS p
             INNER JOIN comment_post_join AS j ON p.post_id = j.post_id
             INNER JOIN forum_comment AS f ON f.comment_id = j.comment_id
             INNER JOIN user_comment_join AS cj ON u.user_id = cj.user_id
             WHERE p.post_id = '$id'
             ORDER BY created_date ASC
         ";

但是我收到以下错误：

Warning: mysqli_fetch_array() expects parameter 1 to be mysqli_result, boolean given in C:\MAMP\htdocs\functions\functions.inc.php on line 963

反过来又指这一行...：

while ($row = mysqli_fetch_array($r)) {

如果我在phpmyadmin中运行此查询，我会得到以下内容：

Unknown column 'u.user_id' in 'field list'

Answer 1

你忘了加入users表。试试这个：

$q = "SELECT p.post_id, f.created_date, f.comment_id, f.comment_content, u.user_id, u.first_name, u.last_name, j.id 
         FROM forum_post AS p
         INNER JOIN comment_post_join AS j ON p.post_id = j.post_id
         INNER JOIN users AS u ON u.user_id = j.user_id
         INNER JOIN forum_comment AS f ON f.comment_id = j.comment_id
         INNER JOIN user_comment_join AS cj ON u.user_id = cj.user_id
         WHERE p.post_id = '$id'
         ORDER BY created_date ASC
     ";

从另一个表

1 个答案: