PHP,, Create Tree Child Parent JSON from DB

tree.php

$data = [
  ['id'=>1, 'id_parent'=>0],
  ['id'=>2, 'id_parent'=>1],
  ['id'=>3, 'id_parent'=>1],
  ['id'=>4, 'id_parent'=>2]
];

$tree = [];
$temp_tree = [];

foreach ($data as $key => $value) {
  if(empty($value['id_parent'])){
    $tree[$value['id']]=[];
  }
  else{
    $tree[$value['id_parent']][$value['id']]=[];
    $temp_tree[$value['id']]=&$tree[$value['id_parent']];
  }
}

foreach ($tree as $key => $value) {
  if(!empty($temp_tree[$key])){
    $temp_tree[$key][$key]=&$tree[$key];
    if(!empty($temp_tree[$key][$key]))
      unset($tree[$key]);
  }
}

die(json_encode($tree));

/*
output :
{
  "1": {
    "2": {
      "4":[]
    },
    "3":[]
  }
}
*/