WordPress两种不需要插件添加相关文章的方法

WordPress的强大和易用，在于无数的主题和插件，但插件多了会影响网站的速度和安全。如果能用简单代码实现需要的功能，还是用代码好了。
在每篇文章的末尾，显示相关文章，可以更好的留住客户。
下面提供两种方法：

第一种

在所用主题的functions.php文件中，添加如下代码

function wp_get_related_posts()
{
global $wpdb, $post,$table_prefix;
$limit = 10; //How Many Related Posts Displayed
if(!$post->ID){return;}
$now = current_time(‘mysql’, 1);
$tags = wp_get_post_tags($post->ID);
$taglist = “‘” . $tags[0]->term_id. “‘”;
$tagcount = count($tags);
if ($tagcount > 1) {
for ($i = 1; $i < $tagcount; $i++) {
$taglist = $taglist . “, ‘” . $tags[$i]->term_id . “‘”;
}
}
$limitclause = “LIMIT $limit”;
$q = “SELECT p.ID, p.post_title, p.post_date,  p.comment_count, count(t_r.object_id) as cnt FROM $wpdb->term_taxonomy t_t, $wpdb->term_relationships t_r, $wpdb->posts p WHERE t_t.taxonomy =’post_tag’ AND t_t.term_taxonomy_id = t_r.term_taxonomy_id AND t_r.object_id  = p.ID AND (t_t.term_id IN ($taglist)) AND p.ID != $post->ID AND p.post_status = ‘publish’ AND p.post_date_gmt < ‘$now’ GROUP BY t_r.object_id ORDER BY cnt DESC, p.post_date_gmt DESC $limitclause;”;
$related_posts = $wpdb->get_results($q);
$output = “”;
if (!$related_posts)
{
$output .= ‘

No Related Posts

’;
}
foreach ($related_posts as $related_post )
{
$dateformat = get_option(‘date_format’);
$output .= ‘

’;
$output .= ‘ID).'” title=”‘.wptexturize($related_post->post_title).’ (‘.mysql2date($dateformat, $related_post->post_date).’)”>’.wptexturize($related_post->post_title).' (‘.$related_post->comment_count .’)’;
$output .= ‘

’;
}
$output = ‘

Related Posts

’ . $output . ‘

’;
return $output;
}
function wp_related_posts_attach($content)
{
if (is_single()||is_feed())
{
$output = wp_get_related_posts();
$content = $content . $output;
}
return $content;
}
add_filter(‘the_content’, ‘wp_related_posts_attach’,100);

第二种

在所用主题的single.php添加，一般添加在之后

Related Posts

$tags = wp_get_post_tags($post->ID);
if ($tags) {
$first_tag = $tags[0]->term_id;
$args=array(
’tag__in’ => array($first_tag),
’post__not_in’ => array($post->ID),
’showposts’=>10,//Display 10 related posts
’caller_get_posts’=>1
);
$my_query = new WP_Query($args);
if( $my_query->have_posts() ) {
while ($my_query->have_posts()) : $my_query->the_post(); ?>

• ” rel=”bookmark” title=””>

endwhile;
}
}
wp_reset_query();
?>