How can I customize Related posts algorithm to show appropriate results

Hi mayurjango. The related posts function “function alx_related_posts()” is in the parent theme functions.php file. You could copy that function (without the “if(!function_exists…” line or the trailing closing bracket “}” line) to your child theme and make your adjustments there. Also, you can set the posts to be related by categories or tags in Theme Options > Blog > Single – Related Posts.

Hi bdbrown,

I guess that would be pretty complicated for me. Is it possible to set the posts to be related by titles as well as tags and/or categories?

I believe you’d need to modify the alx_related_posts function to accomplish that.

Hi bdbrown,

What should I modify or add in below code from functions.php to show related posts by titles as well as tags and/or categories?

/*  Related posts
/* ------------------------------------ */
if ( ! function_exists( 'alx_related_posts' ) ) {

	function alx_related_posts() {
		wp_reset_postdata();
		global $post;

		// Define shared post arguments
		$args = array(
			'no_found_rows'				=> true,
			'update_post_meta_cache'	=> false,
			'update_post_term_cache'	=> false,
			'ignore_sticky_posts'		=> 1,
			'orderby'					=> 'rand',
			'post__not_in'				=> array($post->ID),
			'posts_per_page'			=> 3
		);
		// Related by categories
		if ( ot_get_option('related-posts') == 'categories' ) {

			$cats = get_post_meta($post->ID, 'related-cat', true);

			if ( !$cats ) {
				$cats = wp_get_post_categories($post->ID, array('fields'=>'ids'));
				$args['category__in'] = $cats;
			} else {
				$args['cat'] = $cats;
			}
		}
		// Related by tags
		if ( ot_get_option('related-posts') == 'tags' ) {

			$tags = get_post_meta($post->ID, 'related-tag', true);

			if ( !$tags ) {
				$tags = wp_get_post_tags($post->ID, array('fields'=>'ids'));
				$args['tag__in'] = $tags;
			} else {
				$args['tag_slug__in'] = explode(',', $tags);
			}
			if ( !$tags ) { $break = true; }
		}

		$query = !isset($break)?new WP_Query($args):new WP_Query;
		return $query;
	}

}

Please help.

I reviewed several approaches that use functions, filters and/or SQL queries to get related posts by title. It can be done with code but I think it would take some work to get it right. Searching the database for text strings usually has a higher overhead and, if not optimized, could affect page speed, especially when the search is performed each time a page is served. If you want to base related posts on post title, my suggestion would be to disable the built-in related posts option and use a plugin since the research and development work has already been done and tested. Here are three that might do the trick:
Yet Another Related Posts Plugin (YARPP)
Related Posts for WordPress
Contextual Related Posts