我试图使用下面的代码自动刷新注释，但目前它正在显示所有注释。我只想显示当前帖子的评论。我对SQL不是很有经验，不知道如何执行此操作：

<?php
function dp_recent_comments_ajax() {
        $no_comments = 5;
    $comment_len = 300;
        global $wpdb;

    $request = "SELECT * FROM $wpdb->comments";
    $request .= " JOIN $wpdb->posts ON ID = comment_post_ID";
    $request .= " WHERE comment_approved = \'1\' AND post_status = \'publish\' AND post_password =\'\'";
    $request .= " ORDER BY comment_date DESC LIMIT $no_comments";

    $comments = $wpdb->get_results($request);
    if ($comments) {
        foreach ($comments as $comment) {
            ob_start();
            ?>
                <li>
                    <a style="font-size:12px "href="<?php echo get_permalink( $comment->comment_post_ID ) . \'#comment-\' . $comment->comment_ID; ?>"><?php echo dp_get_author($comment); ?> on <?php echo $comment->comment_date; ?> :</a><br />
                    <span class="recent-comment-text" style="font-size:11px;font-style:italic"><?php echo strip_tags(substr(apply_filters(\'get_comment_text\', $comment->comment_content), 0, $comment_len)); ?>..</span>
                </li>
            <?php
            ob_end_flush();
        }
    } else {
        echo \'<li>\'.__(\'No comments\', \'my-first-wp-theme\').\'</li>\';
    }
    die(); // this is needed for ajax to work properly
}
function dp_get_author($comment) {
    $author = "";

    if ( empty($comment->comment_author) )
        $author = __(\'Anonymous\', \'my-first-wp-theme\');
    else
        $author = $comment->comment_author;

    return $author;
}
add_action(\'wp_ajax_my_recent_comments\', \'dp_recent_comments_ajax\');
add_action(\'wp_ajax_nopriv_my_recent_comments\', \'dp_recent_comments_ajax\'); //for users that are not logged in