Gathering and outputting data by selector of database column - php

Question

I am creating a forum and the code I am putting in this thread is the page that shows all of the forum categories. I have this setup where I have an id, category_section, category_title, and category_description. The way it is structured now is that it creates a new category section border every time I add a new category title in my database. This is what I mean by this:
As an example:
My category section is called Shoes, my category titles are Nike, Adidas, Reebok
Currently, it does:
Shoes
Nike
Shoes
Adidas
Shoes
Reebok
But it should do this:
Shoes
Nike
Adidas
Reebok
How can I get my current code to do this?
$query = mysqli_query($con,"SELECT * FROM forum_categories ORDER BY category_title DESC");
$numrows = mysqli_num_rows($query);
$categories = "";
if($numrows > 0){
while($forum_row = mysqli_fetch_assoc($query)){
$categoryid = $forum_row['id'];
$category_section = $forum_row['category_section'];
$categoryTitle = $forum_row['category_title'];
$categoryDescription = $forum_row['category_description'];
$categories = "<a href='forum_view_category.php?cid=".$categoryid."'>"
. $categoryTitle . "</a>";
//$categories .= "<a href='forum_view_category.php?cid=".$categoryid
//."' class='cat_links'>" . $categoryTitle . "</a>" " - " . $categoryDescription .;
?>
<div class="category_section">
<?php echo $category_section; ?>
</div>
<div class="category_border">
<div class="discussions_left">
<div class="discussions_category_title">
<?php echo $categories; ?>
</div>
<div class="discussions_category_description">
<?php echo $categoryDescription; ?>
</div>
</div>
<div class="discussions_right">
</div>
</div>
<?php
}
//echo $categories;
} else {
echo "<p>There are no posted categories available yet. </p>";
}

Answer 1

I would change your SQL to order by section first, then the title.
SELECT * FROM forum_categories ORDER BY category_section DESC, category_title DESC
After you've done that, define an if statement to check if the current section is the same as the previous statement.
If so, move one.
If not, echo the new section title.
I've cleaned up your code a bit and switched to the Alternative syntax for control structures for readability and maintainability.
PHPFiddle Demo (faked MySQL)
<?php
$query = mysqli_query($con,"SELECT * FROM forum_categories ORDER BY category_section DESC, category_title DESC");
$category_section = "";
?>
<?php if(mysqli_num_rows($query) > 0): ?>
<?php while($cat = mysqli_fetch_assoc($query)): ?>
<?php if($cat['category_section'] !== $category_section): ?>
<?php $category_section = $cat['category_section'] ?>
<div class="category_section">
<?= $category_section ?>
</div>
<?php endif; ?>
<div class="category_border">
<div class="discussions_left">
<div class="discussions_category_title">
<a href="forum_view_category.php?cid=<?= $cat['id'] ?>">
<?= $cat['category_title'] ?>
</a>
</div>
<div class="discussions_category_description">
<?= $cat['category_description'] ?>
</div>
</div>
<div class="discussions_right">
</div>
</div>
<?php endwhile; ?>
<?php else: ?>
<p>There are no posted categories available yet.</p>
<?php endif; ?>