Chapter for Reading story online

I found this code in somewhere. The purpose of this code is listing a list post in the same series; like when reading a book we have chapter 1, 2. 3….

Chapter 1 will be posted in Post type
Chapter 2 will be posted in Story type
Chapter 3 will be posted in Story type
Chapter 4 will be posted in Story type
Chapter 5 will be posted in Story type

What I want is when we are reading chapter 1 there will be a list of all other chapter. When we are reading chapter 2 there will also be a list of on other chapter. So far, this code can only do listing post for Post type but unable to make a list for Story type. Hope you can help me to solve it. ( show list post in the same series in story type)

Create a custom post type.

<?php
add_action( 'init', 'create_post_type' );
function create_post_type() {
register_post_type( 'story',
array(
'labels' => array(
'name' => 'Story',
'singular_name' => 'Story'
),
'show_ui' => true,
'public' => true,
'has_archive' => true,
'taxonomies'    => array('post_tag'), // n?u các b?n mu?n tag cho các ch??ng c?a mình
'rewrite' => array('slug' => 'story', 'with_front' => FALSE),
'supports' => array( 'title', 'editor', 'author', 'excerpt', 'comments' )
)
);
}
?>

Link story to post

<?php
add_action( 'edit_form_after_title', 'mystoryparrent' );
function mystoryparrent( $post_data = false ) {
$scr = get_current_screen();
$value = '';
if ( $post_data ) {
$t = get_post($post_data);
$a = get_post($t->post_parent);
$value = $a->post_title;
}
if ($scr->id == 'story')
echo '<label>Thu?c truy?n: <input type="text" name="parent" value="'.$value.'" /></label> (Tên c?a cu?n truy?n g?c)<br /><br />';
}
?>

Get value for story from post

<?php
add_action( 'save_post', 'save_mystory' );
function save_mystory( $post_id ) {
$story = isset( $_POST['parent'] ) ? get_page_by_title($_POST['parent'], 'OBJECT', 'post') : false ;
if ( ! wp_is_post_revision( $post_id ) && $story ){
remove_action('save_post', 'save_mystory');
$postdata = array(
'ID' => $_POST['ID'],
'post_parent' => $story->ID
);
wp_update_post( $postdata );
add_action('save_post', 'save_mystory');
}
}
?>

Function to show list post in single.php
`<?php
function get_dropdown_part( $id ) {
global $post, $wpdb;
$query = $wpdb->get_results(sprintf(“select * from %s where post_type = ‘%s’ and post_parent = %d and post_status = ‘%s'”, $wpdb->posts, ‘story’, $id, ‘publish’));
if ($query) {
echo ‘

‘;
foreach ( $query as $k ) {
$uri = get_permalink($k->ID);
if ( ! preg_match(‘/.*page-[0-9].*/’, $uri))
echo ‘
• ‘.$k->post_title .’

‘;
}
echo ‘

‘;
}
}
?>’
Demo: https://truyenmoi.mobi/bi-mat-kinh-hoang-trong-quan-net/