Php+mysql method of realizing non-limit classification column _php skill

This paper illustrates the method of Php+mysql to realize the column without limit classification. Share to everyone for your reference, specific as follows:

A very simple and simple example of No limit classification, with indentation effect, just query the data table, and then recursively traverse the result set, you can, in PHP to achieve column indentation display can refer to.

$sql = ' SELECT * from Cat ORDER by cat_id desc ';
$list = $db->getall ($sql);
$list = Getlevelcat ($list);
function Getlevelcat ($catlist, $parent _id= ' 0 ', $html = ', $level = ' 0 ') {
  $arr = array ();
  foreach ($catlist as $val) {
    if ($val [' parent_id ']== $parent _id) {
      $val [' html '] = Str_repeat ($html, $level);
      $val [' level '] = $level;
      $arr [] = $val;
      $arr = Array_merge ($arr, Getlevelcat ($catlist, $val [' cat_id '], $html, $level + 1));
    }
  return $arr;
}

To implement the effect diagram:

A few lines of code, more clear, but also more useful.

I hope this article will help you with the PHP program design.