Issue in pulling pages from the database - php

Question

I am having problems pulling the pages through in PHP and HTML I have used :-
<li>
<!-- Pulling Categories from the database
dynamically -->
<?php
$nav_subjects = find_all_subjects(['visible' => $visible]);
while($nav_subject =
mysqli_fetch_assoc($nav_subjects)) {
?>
<span class="opener"><?php echo h($nav_subject['menu_name']); ?></span>
Which pulls the categories dynamically from the database and displays them with a drop down arrow just how I wanted but the pages will not show underneath them here's the code I have used for that bit:-
<!-- Categories listed correctly let's pull the pages for each one -->
<?php
if($nav_subject['id'] == $subject_id) {
$nav_pages = find_pages_by_subject_id($nav_subject['id'], ['visible' => $visible]);
while($nav_page = mysqli_fetch_assoc($nav_pages)) {
?>
<ul>
<li>
<?php echo h($nav_page['menu_name']); ?>
</li>
</ul>
<?php } // while $nav_pages
} // if($nav_subject['id'] == $subject_id)
} // while $nav_subjects ?>
</li>
<?php
mysqli_free_result($nav_subjects);
mysqli_free_result($nav_pages);
?>
I am pulling in the SQL from another page which is loaded correctly as the categories load and display correctly.
I will be grateful for any ideas.
I have also tried to echo back the sql result but nothing is shown.
I have now got it working with the following code:-
<li>
<?php $nav_subjects = find_all_subjects(['visible' => $visible]);
while($nav_subject = mysqli_fetch_assoc($nav_subjects)) {?>
<span class="opener"><?php echo h($nav_subject['menu_name']); ?></span>
<ul>
<?php if($nav_subject['id'] == $subject_id);
$nav_pages = find_pages_by_subject_id($nav_subject['id'], ['visible' => $visible]);
while($nav_page = mysqli_fetch_assoc($nav_pages)) { ?>
<li><?php echo h($nav_page['menu_name']); ?></li>
<?php } ?>
<?php } ?>
</ul>
But now it is listing the secondary subjects as a child of the first instead of individual subjects of their own.
*********Resolved**********
please advise if you think the code could be better i've currently used :-
<li>
<?php $nav_subjects = find_all_subjects(['visible' => $visible]);?>
<?php while($nav_subject = mysqli_fetch_assoc($nav_subjects)){?>
<span class="opener"><?php echo h($nav_subject['menu_name']);?></span>
<ul>
<?php if($nav_subject['id'] == $subject_id);
$nav_pages = find_pages_by_subject_id($nav_subject['id'], ['visible' => $visible]);
while($nav_page = mysqli_fetch_assoc($nav_pages)) { ?>
<a href="<?php echo url_for('index.php?id=' . h(u($nav_page['id']))); ?>">
<?php echo h($nav_page['menu_name']); ?></a>
<?php } ?>
<?php mysqli_free_result($nav_pages); ?>
</ul>
<?php } ?>
<?php mysqli_free_result($nav_subjects); ?>
</li>