如何按类别显示与当前 post 的下一个 post 相关的 post（不要最新 post 或随机 post）

Question

如何按类别显示与当前 post 的下一个 post 相关的 post（不要最新 post 或随机 post）。我使用与 twentytwelve 主题相关的代码 post。但是现在，wentytwelve_entry_meta() 中的作者重复了。

请帮助我：

<div id="related_posts">
    <?php
        $categories = get_the_category($post->ID);
        if ($categories) {
            $category_ids = array();
            foreach((get_the_category()) as $category) {
                $id = $category->cat_ID;
            }
            global $wpdb;
            $query = "
                SELECT * FROM $wpdb->posts
                LEFT JOIN $wpdb->term_relationships ON
                ($wpdb->posts.ID = $wpdb->term_relationships.object_id)
                LEFT JOIN $wpdb->term_taxonomy ON
                ($wpdb->term_relationships.term_taxonomy_id = $wpdb->term_taxonomy.term_taxonomy_id)
                WHERE $wpdb->posts.post_status = 'publish'
                AND $wpdb->term_taxonomy.taxonomy = 'category'
                AND $wpdb->term_taxonomy.term_id = $category_ids[0]
                AND $wpdb->posts.id < $post->ID
                ORDER BY id DESC limit 3
           ";
           $my_query = $wpdb->get_results($query);
           if( $my_query) {
               echo '<h3>Related Posts</h3><ul>';
               foreach($my_query as $key => $post) {
               ?>
                   <li>
                        <div class="entry-header">
                            <div class="header-l">
                                 <h1 class="entry-title">
                                      <a href="<?php the_permalink(); ?>" title="<?php echo esc_attr( sprintf( __( 'Permalink to %s', 'twentytwelve' ), the_title_attribute( 'echo=0' ) ) ); ?>" rel="bookmark"><?php the_title(); ?></a>
                                </h1>
                                <p class="datetime">
                                    <?php twentytwelve_entry_meta(); ?>
                                </p>
                            </div>
                            <?php the_post_thumbnail(); ?>
                      </div>

                      <div class="entry-summary">
                          <?php
                              $str_content = wp_trim_words($post->post_content);
                              $str_content = str_replace('[', '<', $str_content);
                              $str_content = str_replace(']', '>', $str_content);
                              echo $str_content;
                          ?>
                     </div>
                </li>
           <?php
           }
           echo '</ul>';
       }
   }?>

Answer 1

WordPress习惯上是使用WP_Queryclass从数据库中获取posts，如果你可以修改你的代码使用WP_Query会更容易。

WP_Query Reference

当您使用自定义查询从数据库加载 post 时，the_permalink()、the_title_attribute()、the_title() 等模板标签将无法正常工作，即主题功能 twentytwelve_entry_meta() 失败的原因。

根据法典参考 Displaying Posts Using a Custom Select Query

你应该尝试这样的事情：

global $wpdb;
$query = "
    SELECT * FROM $wpdb->posts
    LEFT JOIN $wpdb->term_relationships ON
    ($wpdb->posts.ID = $wpdb->term_relationships.object_id)
    LEFT JOIN $wpdb->term_taxonomy ON
    ($wpdb->term_relationships.term_taxonomy_id = $wpdb->term_taxonomy.term_taxonomy_id)
    WHERE $wpdb->posts.post_status = 'publish'
    AND $wpdb->term_taxonomy.taxonomy = 'category'
    AND $wpdb->term_taxonomy.term_id = $category_ids[0]
    AND $wpdb->posts.id < $post->ID
    ORDER BY id DESC limit 3";

$my_query = $wpdb->get_results($query);

if($my_query) {
    global $post;
    echo '<h3>Related Posts</h3><ul>';
    foreach($my_query as $key => $post) {
        //use setup postdata, it works only for variable named $post.

        setup_postdata($post); 
        //you can safely use template tags now.

        ?>
        <li>
            <div class="entry-header">
                <div class="header-l">
                    <h1 class="entry-title">
                        <a href="<?php the_permalink(); ?>" title="<?php echo esc_attr( sprintf( __( 'Permalink to %s', 'twentytwelve' ), the_title_attribute( 'echo=0' ) ) ); ?>" rel="bookmark"><?php the_title(); ?></a>
                    </h1>
                    <p class="datetime">
                        <?php twentytwelve_entry_meta(); ?>
                    </p>
                </div>
                <?php the_post_thumbnail(); ?>
            </div>


            <div class="entry-summary">
              <?php
                  $str_content = wp_trim_words($post->post_content);
                  $str_content = str_replace('[', '<', $str_content);
                  $str_content = str_replace(']', '>', $str_content);
                  echo $str_content;
              ?>
            </div>
        </li>
        <?php
    }
}

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