Or, you can place this code in your active theme’s functions.php:
<?php
// First, backup the default $postdata
$backup = $post;
// Now, override the default
$tags = wp_get_post_tags($post->ID);
// Now, open the if ( $tags ) statement
if ($tags) {
$tag_ids = array();
foreach($tags as $individual_tag) $tag_ids[] = $individual_tag->term_id;
// Now, setup your custom query args
$args=array(
'tag__in' => $tag_ids,
'post__not_in' => array($post->ID),
'showposts'=>10, // Number of related posts that will be shown.
'ignore_sticky_posts'=>1
);
// Now, perform your custom query
$my_query = new wp_query($args);
// Next, open your custom query IF statement
if( $my_query->have_posts() ) {
// We have posts, so let's output the opening-containing markup
?>
<div class="relatedposts">
<h3>RELATED:</h3>
<?php
// Now, open your custom query WHILE statement
while ($my_query->have_posts()) {
$my_query->the_post();
?>
<ul><li> <a href="https://wordpress.stackexchange.com/questions/47143/<?php the_permalink() ?>" rel="bookmark" title="Permanent Link to <?php the_title_attribute(); ?>"><?php the_title(); ?></a></li></ul>
<?php
// Now, close the while $my_query->have_posts() statement
}
// Now, output your closing-containing HTML content
?>
</div>
<?php
// Now, close the if $my_query->have_posts() statement
// and open the ELSE statement, for your no-posts content
} else {
?>
<?php // If there are no related posts ?>
<p class="noposts">FURTHER READING: <span>You may find more posts like this by searching the site...</span></p>
<?php
// Now, close the ELSE statement
}
// Now, close the if ( $tags ) statement
}
// Now, reset the default query
$post = $backup;
wp_reset_query();
?>