I resolved the problem adding a new custom post type called ANNO and 1 relationship field called anno_issue from year to issue_number.
The code is this for query :
` <?php
// args
$args = array(
‘numberposts’ => -1,
‘post_type’ => ‘anno’,
‘posts_per_page’ => 100,
);
// query
$the_query = new WP_Query( $args );
?>
<?php while( $the_query->have_posts() ) : $the_query->the_post();
mh_before_page_content();
mh_magazine_page_title();?>
<?php
/*
* Query posts for a relationship value.
* This method uses the meta_query LIKE to match the string “123” to the database value a:1:{i:0;s:3:”123″;} (serialized array)
*/
$posts = get_posts(array(
‘post_type’ => ‘issue_number’, //nome post type da dove recupero le info
‘posts_per_page’ => -1,
‘meta_query’ => array(
array(
‘key’ => ‘anno_issue’, // nome custom field all’interno di post che mi da l’info
‘value’ => ‘”‘ . get_the_ID() . ‘”‘, // matches exaclty “123”, not just 123. This prevents a match for “1234”
‘compare’ => ‘LIKE’
)
)
));
?>
<?php /*ciclo stampa articoli */ ?>
<?php if( $posts ): ?>
<?php foreach( $posts as $post ): ?>
<?php /*layout 1 del tema per articoli */ ?>
<article >
—HTML CODE DISPLAYNG YOUR LOOP—
</article>
<?php /*fine layout 1 */ ?>
<?php endforeach; ?>
<?php endif; ?>
<?php /*fine ciclo stampa articoli */ ?>
<?php endwhile; // end of the loop. ?>
