php处理三级分类数据

<?php

// 链接数据库
$link = mysqli_connect(‘localhost‘,‘root‘,‘root‘);
if($link == null){
　　exit;
}
mysqli_select_db($link,‘test‘);
$link->query("SET NAMES utf8");
$sql = "select * from tp_goods_categorys";
$res = mysqli_query($link,$sql);

while($res && $row = mysqli_fetch_assoc($res)) {
  $list[] = $row;
}
echo ‘<pre>‘;
print_r(res($list)); 
function res($items){
    $tree = array();
    foreach($items as $key =>$val){
            $list = explode(‘,‘,$val[‘categorys_path‘]);
            switch(count($list)){
                case 1:
                    $tree[$val[‘id‘]] = $val;
                    break;
                case 2:
                    $tree[$val[‘categorys_pid‘]][‘son‘][$val[‘id‘]] = $val;
                    break;
                case 3:
                    $tree[$list[1]][‘son‘][$list[2]][‘son‘] = $val;
                    break;
            }
    }
    return $tree;
}