hierarchial two dimetional php array from an two dimetional php - php

Question

I have a multiD array containing all users like below.
Array
(
[0] => Array
(
[username] => santoshe62
[sponsor] => santoshe61
)
[1] => Array
(
[username] => santoshe63
[sponsor] => santoshe62
)
[2] => Array
(
[username] => santoshe65
[sponsor] => santoshe64
)
[3] => Array
(
[username] => santoshe67
[sponsor] => santoshe66
)
.............................
)
I want an array from this array containing hierarchical data of given user like below.
Array
(
[0] => Array
(
[username] => santoshe62
[sponsor] => santoshe61
)
[1] => Array
(
[username] => santoshe63
[sponsor] => santoshe62
)
)
I have tried
function parseTree($datas, $parent = 0){
$tree = array();
for($i=0, $ni=count($datas); $i < $ni; $i++){
if($datas[$i]['sponsor'] == $parent){
$tree[] = $datas[$i];
parseTree($datas, $datas[$i]['username']);
}
}
return $tree;
}
Can anybody help me by finding what is wrong in my code? Also please suggest, can I select only this hierarchical structure directly from MySQL? Now I am selecting all results from DB.

Answer 1

The problem is because of this statement in your function, $tree = array();. In each recursive function call, this $tree is getting initialized with an empty array. You have to declare it as static variable, so that it could get initialized only once and could retain its state in recursive function calls.
function parseTree($datas, $parent = 0){
static $tree = array();
...
}