displaying subcategories under the categories in oscommerce - php

Question

Here is the markup of what I have so far:
<?php
$categories_query = tep_db_query("select c.categories_id, cd.categories_name, c.categories_image, c.parent_id, c.sort_order, c.date_added, c.last_modified from " . TABLE_CATEGORIES . " c, " . TABLE_CATEGORIES_DESCRIPTION . " cd where c.categories_id = cd.categories_id order by c.sort_order ASC");
while ($categories = tep_db_fetch_array($categories_query)){
echo '<tr class="dataTableRow">
<td class="dataTableContent">' . $categories ['categories_name'] . '</td>';
?>
<td class="dataTableContent"></td>
<?php
echo '</tr>';
}
?>
This displays all the categories and subcategories all on a page, but in no order, what i need is for the subcategories to be displayed under the main category. I have some clue as to how i would do it, a link between the sort_order field and the parent_id field. The main categories use the sort_order field as id, and the subccat's use the parent_id field to sort the category they belong to. Any ideas?

Answer 1

I'm not sure how to do display category tree with single MySQL query, so I'm suggesting to use recursive PHP function:
<?php
function showChildCategories($parent) {
$parent = intval($parent);
// Select only categories with parent_id = $parent
$categories_query = tep_db_query("select
cd.categories_name,
c.categories_id
from " . TABLE_CATEGORIES . " c, " .
TABLE_CATEGORIES_DESCRIPTION . " cd
where c.categories_id = cd.categories_id
and c.parent_id = $parent
order by c.sort_order ASC");
// Go through all query result rows
while ($categories = tep_db_fetch_array($categories_query)){
// Show category name
echo '<tr class="dataTableRow"><td class="dataTableContent">' .
$categories ['categories_name'] . '</td></tr>';
// Show child categories for current row
showChildCategories($categories ['categories_id']);
} // while
} // function showChildCategories
// Show top-level categories and all their children recursively
showChildCategories(0);
?>