Nested category parent id - php

Question

i have mysql table (exe_categories)
| id, title, parent_id, extension |
`<ul>
<li>Parentcat</li>
<ul>
<li>ParentSub</li>
<li>ParentSub</li>
<li>ParentSub</li>
</ul>
<li>Parentcat</li>
<ul>
<li>ParentSub</li>
<li>ParentSub</li>
<li>ParentSub</li>
</ul>
</ul>`
and i want to show a nested category list and subcategory using 2 arguments
first-argument is (parent_id) (0)
AND second argument is (extension) 'com_extension'
I want to show up the nested categories titles and path for the 2 arguments above
i have used this code below and works fine but i cant have another argument for extension argument.
<?php
function query($parent_id) { //function to run a query
$query = mysql_query ( "SELECT * FROM exe_categories WHERE parent_id=$parent_id");
return $query;
}
function has_child($query) { //This function checks if the menus has childs or not
$rows = mysql_num_rows ( $query );
if ($rows > 0) {
return true;
} else {
return false;
}
}
function fetch_menu($query) {
while ( $result = mysql_fetch_array ( $query ) ) {
$id = $result ['id'];
$extension = $result['com_bids'];
$title = $result ['title'];
$menu_link = $result ['menu_link'];
echo "<li><a href='{$menu_link}'><span>{$title}</span></a>";
if (has_child ( query ( $id ) )) {
echo "<div>";
echo '<ul role="menu" class="fofc">';
fetch_menu ( query ( $id) );
echo "</ul>";
echo "</div>";
}
echo "</li>";
}
}
fetch_menu (query(1)); //call this function with 1 parent id
?>
the code above will fetch list of categories starting from parent_id=0 which works great only that i cant have another rule for my extension column .
any help will be appreciated :)
The Html output is like this
Parentcat
ParentSub
ParentSub
ParentSub
Parentcat
ParentSub
ParentSub
ParentSub