drop down menu from database - php

Question

I am want to make a navigation menu with a sub menu on hover. I want to get this data from my database (to make it dynamic if data in database changes menu bar changes). In my database I have a table with the the following fields:
ID, Name, Level, Parent_id. Level can be 0 or 1. 0 for main menu 1 for sub menu the id of a main menu is tied to the parent_id field.
So for instance:
ID Name Level Parent_id
1 Test 0
2 Test2 0
3 Test_sub 1 1
4 Test_sub2 2 2
I have managed to get the main menu items from the db but now I am a little bit stuck. This is my code any help would be appriciated.
<?php
$q2= "SELECT * from menu where level = 0 ";
$q2result = $db->query($q2);
while($a2 = $q2result->fetch(PDO::FETCH_ASSOC)){
echo "
<ul>
<li><a href='#' ><span> " . $a2['name'] . " </span></a>
<ul>
<li><a href='#' ><span> test </span></a></li>
</ul>
</ul>
";
}
?>

Answer 1

First load all your datas into variables. Never print/echo while in SQL statement.
<?php
$q2= "SELECT * FROM menu ORDER BY Level ASC";
$q2result = $db->query($q2);
$nodes=array();
while($a2 = $q2result->fetch(PDO::FETCH_ASSOC)){
// assuming one parent node has already been assigned, due do level order into the SQL
if($node['Level']>0 && isset($nodes[$a2['id']])) {
$nodes[$a2['id']]['nodes'][]=$a2;
} else {
// parent node
$nodes[$a2['id']]=$a2;
$nodes[$a2['id']]['nodes']=array();
}
}
print "<ul>";
foreach($nodes as $node) {
print "<li>";
print "<a href='#'>".$node['Name']."</a>";
if(sizeof($node['nodes'])>0) {
print "<ul>";
foreach($node['nodes'] as $subnode) {
print "<li><a href='#'>".$subnode['Name']."</a></li>";
}
print "</ul>";
}
print "</li>";
}
print "</ul>";
?>
This may be much more improved, but with this, you can do what you ask, and improve it.