Using query_posts with custom fields - php

Question

I have a custom post type called "books".
This post type has a custom field called "release-date" that contains a unix timestamp.
I'm working on WordPress archive.php page to have a list of books and I'm trying to alterate the main query.
What I need is to have only books with release-date > today and sorted by release-date.
This is what I try to sort it:
global $query_string;
query_posts( $query_string . "&meta_key=release-date&orderby=meta_value_num&order=ASC&posts_per_page=9" );
The sorting seems not working as expected.

Answer 1

I think that by now you should use the WP_Query class:
$args = array(
'post_type' => 'books',
'meta_query' => array (
'key' => 'release-date',
'value' => date('d/m/Y',strtotime("today")),
'type' => 'DATE',
'compare' => '>='
),
'meta_key' => 'release-date',
'orderby' => 'meta_value_num',
'order' => 'DESC'
);
and then, just
$your_query = new WP_Query( $args );
if ($your_query->have_posts()) {
while ( $jobs_query->have_posts() ) {
$your_query->the_post();
var_dump($post)
}
}
More info here

Answer 2

So if u want only post where release-date is bigger than today you can do an easy wp-query to get all post:
function getPostsByQuery(WP_Query $query)
{
$posts = array();
if ($query->have_posts()) {
while ($query->have_posts()) {
$query->the_post();
$posts[] = $query->post;
}
wp_reset_postdata();
}
return $posts;
}
function getPostsByCustomemField($name, $limit = -1)
{
return getPostsByQuery(new WP_Query(array('post_type'=>'books','meta_key' => $name, 'posts_per_page' => $limit)));
}
function getBooks() {
$posts = getPostsByCustomemField('release-date');
$books = [];
foreach ($posts as $post) {
if (get_post_meta($post->ID,'release-date',true) > date('d/m/Y',strtotime("today"))) {
$books[] = $post;
}
}
return $books;
}