<?php
$args = array(
'post_type' => 'publication',
'posts_per_page' => '-1',
'meta_query' => array(
'relation' => 'OR',
array(
'key' => 'publication_order',
'compare' => 'EXISTS'
)
),
'meta_key' => 'publication_order',
'orderby' => 'meta_value',
'order' => 'ASC'
);
$loop = new WP_Query($args);
$liste_sticky = [];
while ( $loop->have_posts() ) : $loop->the_post();
$liste_sticky[] = get_the_ID();
get_template_part('parts/publications/loop', 'publications');
endwhile;
wp_reset_postdata();
$args = array(
'post_type' => 'publication',
'posts_per_page' => '-1',
'post__not_in' => $liste_sticky,
'meta_key' => 'publication_year',
'orderby' => 'meta_value',
'order' => 'DESC'
);
$loop = new WP_Query($args);
while ( $loop->have_posts() ) : $loop->the_post();
get_template_part('parts/publications/loop', 'publications');
endwhile;
wp_reset_postdata();
?>