How to create a nested menu from MySQL with PHP? - php

Question

I need to create a menu with PHP from a MySQL database.
Table called categories has id, name, parent_id, shortdesc, etc.
The output need to have parent list and children list under the partent list as follows.
If you can show me codes or website, I will appreciate it.
<ul id="catmenu">
<li class="menulist">Cars
<ul>
<li>Ford</li>
<li>Honda</li>
<li>Toyota</li>
</ul>
</li>
<li class="menulist">Food
<ul>
<li>Pasta</li>
<li>Pizza</li>
...
</ul>
</li>
...
...
</ul>

Answer 1

This is specifically for two levels deep. Recommended approach should it be more is to use an optimized table structure for traversal, like http://articles.sitepoint.com/article/hierarchical-data-database/2 (pointed out elsewhere) or to pull the data you need and push it into a dictionary (associative array) and query it that way.
<?php
$query = <<<EOT
SELECT
parent.name as parent_name,
child.name as child_name,
FROM
items child
INNER JOIN
items parent
ON
child.parent_id = parent.id
ORDER BY
parent.name
EOT;
$result = mysql_query($query) or die('Failure!');
echo "<ul id=\"catmenu\">";
$last_parent = '';
while($row = mysql_fetch_array($result)){
// If this is a new category, start a new one
if($last_parent != $row['parent_name']){
// Unless this is the first item, close the last category
if($last_parent != ''){
echo "</ul></li>";
}
$last_parent = $row['parent_name'];
echo "<li class=\"menulist\">{$row['parent_name']}<ul>";
}
echo "<li>{$row['child_name']}</li>";
}
// If we actually had items, close the "category"
if($last_parent != ''){
echo "</ul></li>";
}
echo "</ul>";
?>

Answer 2

If you have only two levels then, you could just display them :
echo '<ul id="catmenu">';
foreach($menu as $element) {
echo '<li><ul class="menulist">';
foreach($element['submenu'] as $submenu) {
echo '<li>' . $submenu['name'] . '</li>';
}
echo '</ul></li>';
}
echo '</ul>
If you have an undefined number of submenus however you should use a Recursive Function.
function menu($item) {
$ret = '<li>' . $item['name'];
if (!empty($item['submenu'])) {
foreach($item['submenu'] as $submenu) {
$ret .= menu($submenu);
}
}
return $ret;
}
echo menu($menu);
So every of your subcategories, whatever their number is will be displayed.

Answer 3

You make database like this.
ID NAME PARENT
0 Cars -1
1 Foods -1
2 Ford 0
3 Honda 0
4 Toyota 0
5 Pasta 1
6 Pizza 1
...
You query them all up and put it in an array.
$Menus = array();
// In a read MySQL loop
$Menus[$i]['ID']
$Menus[$i]['NAME']
$Menus[$i]['PARENT']
// Sorry, lazy to write. I think you know what I mean.
Then you loop all menu looking for PARENT == -1. Generate all UL and IL then sub it with another nested menu.
You can simply create a function like this.
var $MenuLevelClass = array("menulist");
function CreateMenu($Menus, $Tab = 0, $Parent = -1, $Level = 0) {
global $MenuLevelClass;
$CatClass = ($Level != 0) ? '' : ' class="catmenu"';
$MenuClass = $MenuLevelClass[$Level];
if ($MenuClass != '')
$MenuClass = ' class="'.$MenuClass.'"';
$TabCount = $Level + $Tab;
$TabUL = "";
for ($t = 0; $t < $TabCount; $t++)
$TabUL = $TabUL."\t";
$TabLI = $TabUL."\t";
?>
<?=$TabUL?><ul<?=$CatClass?>>
<?php
$MenuCount = count($Menus);
for ($m = 0; $m < $MenuCount; $m++) {
$Menu = $Menu[$m];
$ID = $Menu['ID'];
if ($ID != $Parent)
continue;
?>
<?=$TabLI?><li<?=$MenuClass?>><?=$Menu['Name']?><?=CreateMenu($Menus, $Tab + 1, $ID, $Level + 1)?></li>
<?php
?>
<?=$TabUL?></ul>
<?php
}
}
And to use it just run 'CreateMenu($Menus);' or 'CreateMenu($Menus, $PrefixTabCount);'.
CreateMenu will recursively create the nested menu for you.
I have not test it so you may have to adjust it.
Hope this helps.