Get Categories (multiple levels) - php

Question

I am making a script which will load all categories from a database. I just don't know how I can do this in a way which is shorter.
I am trying to figure out a way in which I can theoretically load infinite levels of categories.
$stmt1 = $db->query("SELECT * FROM Rubriek WHERE Hoofdrubriek IS NULL");
while($row1 = $db->fetch($stmt1))
{
$stmt2 = $db->query("SELECT * FROM Rubriek WHERE Hoofdrubriek = '" . $row1['Rubrieknummer'] . "'");
while($row2 = $db->fetch($stmt2))
{
$stmt3 = $db->query("SELECT * FROM Rubriek WHERE Hoofdrubriek = '" . $row2['Rubrieknummer'] . "'");
while($row3 = $db->fetch($stmt3))
{
$stmt4 = $db->query("SELECT * FROM Rubriek WHERE Hoofdrubriek = '" . $row3['Rubrieknummer'] . "'");
while($row4 = $db->fetch($stmt4))
{
$row3['CATEGORY3'][] = array(
'CATEGORY4_NAME' => ucfirst(strtolower($row4['Rubrieknaam'])),
);
}
$row2['CATEGORY3'][] = array(
'CATEGORY3_NAME' => ucfirst(strtolower($row3['Rubrieknaam'])),
'CATEGORY4' => $row2['CATEGORY4'],
);
}
$row1['CATEGORY2'][] = array(
'CATEGORY2_NAME' => ucfirst(strtolower($row2['Rubrieknaam'])),
'CATEGORY3' => $row2['CATEGORY3'],
);
}
$catagories[] = array(
'CATEGORY_NAME' => ucfirst(strtolower($row1['Rubrieknaam'])),
'CATEGORY2' => $row1['CATEGORY2'],
);
}
I would like to have some ideas on how to make this happen.
(I am using a little template system that processes the array that is being made)
EDIT:
Thanks to Ivijan Stefan Stipić I was able to solve this.
This is what I ended up doing
$categories = build_category(0);
And the function:
function build_category($parent, $row = NULL)
{
global $db;
// Initialise array
$data = array();
// Basic SQL statement
$sql = "SELECT * FROM Rubriek";
// Where condition based on $row
if(is_null($row))
{
$where = " WHERE Hoofdrubriek IS NULL";
}
else
{
$where = " WHERE Hoofdrubriek = '" . $row['Rubrieknummer'] . "'";
}
// Execute query
$stmt = $db->query($sql . $where);
// Next level parent
$next = $parent + 1;
// Fetch results
while($row = $db->fetch($stmt))
{
$data[] = array(
'CATEGORY' . $parent . '_NAME' => ucfirst(strtolower($row['Rubrieknaam'])),
'CATEGORY' . $next => build_category($next, $row),
);
}
// Return data
return $data;
}

Answer 1

What do you think about this solution?
function next_level($val)
{
global $db;
$stmt = $db->query("SELECT * FROM Rubriek WHERE Rubrieknummer != '" .$val. "' AND Hoofdrubriek = '" .$val. "'");
while($row = $db->fetch($stmt))
{
echo ucfirst(strtolower($row['Rubrieknaam']));
echo next_level($row['Rubrieknummer']);
}
}
$stmt = $db->query("SELECT * FROM Rubriek WHERE Hoofdrubriek IS NULL");
while($row = $db->fetch($stmt))
{
echo ucfirst(strtolower($row['Rubrieknaam']));
echo next_level($row['Rubrieknummer']);
}
If I understand correctly this is the number of categories with unlimited subcategories.