从联接表

Question

我从数据库中提取行，这些行也会显示帖子的响应数。我能够抓住行，但是需要对连接表中的帖子进行统计，这需要post_id和comment_id - 我不确定如何处理这个或者它是否可行？

function build_forum_featured(){    

    global $dbc;

    $q = "SELECT u.user_id, u.first_name, u.last_name, f.post_created, f.post_id, f.post_title, 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 featured_post = 2
             ORDER BY post_created ASC
    ";  

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



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

    echo '
    <div class="post">
        <div class="col-group-2">
            <a href="post_view.php?post_id='.$row["post_id"].'"><h3>'.$row["post_title"]. '</h3></a>
            <p>By: <a href="user_view.php?id=' . $row["user_id"] . '">'.$row["first_name"] . ' ' .$row["last_name"]. '</a> on: ' .date('d-m-Y', strtotime($row["post_created"])). '</p>
        </div>

        <div class="col-group-2">
            <div class="post_count">
                <h3  class="answer">0</h3> // count goes here!
                <p class="answer">Responses</p>
            </div>
        </div>  
    </div>
    ';

    } 

基本上我在trykgi上做的是引用连接表并检查post_id以及与该帖子关联的注释数量。所以我有一个名为comment_post_join的表，它接受post_id和comment_id，只添加行。

Answer 1

在您的列列表中添加一个计数（*），以便在语句结尾处按user_id，post_id选择并添加一个组...