How to change order with next and previous button

• Julien

• December 12, 2017 at 9:29 pm

Hi,
I have a problem to order single post by a custom field when I navigate with prev and next button. I have a code to change the order by title which works, but I can’t figure out how to use a custom field instead. Is there a way to do it ?

Here is my code in my single.php

<?php
	function mytheme_previous_post_orderby_name($orderby){
	    return "ORDER BY p.post_title DESC LIMIT 1";
	}
	function mytheme_previous_post_where_name(){
	    global $post, $wpdb;
	    return $wpdb->prepare( "WHERE p.post_title < %s AND p.post_type = %s AND ( p.post_status = 'publish' OR p.post_status = 'private' )", $post->post_title, $post->post_type );
	}
	function mytheme_next_post_orderby_name($orderby){
	    return "ORDER BY p.post_title ASC LIMIT 1";
	}
	function mytheme_next_post_where_name(){
	    global $post, $wpdb;
	    return $wpdb->prepare( "WHERE p.post_title > %s AND p.post_type = %s AND ( p.post_status = 'publish' OR p.post_status = 'private' )", $post->post_title, $post->post_type );
	}
	add_filter('get_previous_post_sort', 'mytheme_previous_post_orderby_name', 10, 1);
	add_filter('get_next_post_sort', 'mytheme_next_post_orderby_name', 10, 1);

	add_filter('get_previous_post_where', 'mytheme_previous_post_where_name', 10);
	add_filter('get_next_post_where', 'mytheme_next_post_where_name', 10);
?>
<div>
	 <?php previous_post_link('%link', 'previous', TRUE); ?>
	 <?php next_post_link('%link', 'next', TRUE); ?>
</div>
<?php
	remove_filter('get_previous_post_sort', 'mytheme_previous_post_orderby_name', 10);
	remove_filter('get_next_post_sort', 'mytheme_next_post_orderby_name', 10);
	remove_filter('get_previous_post_where', 'mytheme_previous_post_where_name', 10);
	remove_filter('get_next_post_where', 'mytheme_next_post_where_name', 10);
?>

I searched already, but I can’t find any solution to that problem,
thanks !