Tree issue in PHP - php

Question

i have a table General whose structure like this
----------------------------------
id | name | parent_id
------------------------------------
1 | root_category | Null
2 | Appare | 1
3 | Accessories | 1
4 | Shirt | 2
5 | Pants | 2
6 | hand Bags | 3
7 | jewelry | 3
And i store the value of general table using from in my product table
product table which contain all the information about product
in product table
p_id | 1
p_name | bla
p_weight | 250
g_id | 5
g_name | pants
g_parent | 2
i Want to generate complete tree using
->g_id -> g_name -> g_parent
tree should look like this
Root Category
- Apparel
-- Shirts
-- Pants
- Accessories
-- Handbags
-- Jewelry
i have tried recursive function but its not working which is
function get_categories($parent = $g_parent)
{
$html = '<ul>';
$query = mysql_query("SELECT * FROM `general` WHERE `parent_id` = '$parent'");
while($row = mysql_fetch_assoc($query))
{
$current_id = $row['id'];
$html .= '<li>' . $row['name'];
$has_sub = NULL;
$has_sub = mysql_num_rows(mysql_query("SELECT COUNT(`parent_id`) FROM `general` WHERE `parent_id` = '$current_id'"));
if($has_sub)
{
$html .= get_categories($current_id);
}
$html .= '</li>';
}
$html .= '</ul>';
return $html;
}
print get_categories();
but its not working.... :(

Answer 1

You should try this... its working code.. also see the output screenshot (output screen)
<?php
function get_categories(){
$con = mysql_connect("localhost","root","");
if (!$con){
die('Could not connect: ' . mysql_error());
}
mysql_select_db("stackoverflow", $con);
$result = mysql_query("SELECT g.`name` AS `category`, GROUP_CONCAT(gj.`name`) AS `name`
FROM `general` g INNER JOIN `general` gj ON g.`id` = gj.`parent_id` GROUP BY g.`id` ");
$i=0;
while($row = mysql_fetch_array($result)){
$data[$i]['category'] = $row['category'];
$data[$i]['name'] = $row['name'];
$i++;
}
$html = $data[0]['category']."<br>";
unset($data[0]);
foreach($data as $key => $listing){
$html .= " - ".$listing['category']."<br>";
$exp = explode(",",$listing['name']);
$count_exp = count($exp);
for($j=0; $j<=$count_exp-1;$j++){
$html .= " -- ".$exp[$j]."<br>";
}
}
return $html;
}
print_r(get_categories());
?>
Output Screen

Answer 2

Change this
print get_categories();
To
print get_categories(1);
an empty string is not going to match a NULL value in MySQL, hence you need to supply your starting id. Unless you wanna modify your function to do the extra checking if $parent is null.

Answer 3

try this with some changing :
function get_categories($parent)
{
$html = '<ul>';
$query = mysql_query("SELECT * FROM `general` WHERE `parent_id` = '$parent'");
while($row = mysql_fetch_assoc($query))
{
$current_id = $row['id'];
$html .= '<li>' . $row['name'];
$has_sub = NULL;
$has_sub = mysql_num_rows(mysql_query("SELECT COUNT(`parent_id`) as count FROM `general` WHERE `parent_id` = '$current_id'")); // change here
if($has_sub['count'] > 0) // change here
{
$html .= get_categories($current_id);
}
$html .= '</li>';
}
$html .= '</ul>';
return $html;
}
print get_categories(1); // change here