php实现数据树形结构 递归方法

//2.定义递归查询 数据格式化
public function data($pid=0){
$data = \DB::table('types')->where('pid',$pid)->get();
foreach ($data as $key=>$val){
$val->zi = $this->data($val->id);
}
return $data;
}
//3.递归查询 数据格式化
public function data1($data,$pid=0){
$newArr = array();
//获取顶级分类
foreach ($data as $key=>$val){
if ($val->pid == $pid){
$newArr[$val->id] = $val;
$newArr[$val->id]->zi = $this->data1($data,$val->id);
}
}
return $newArr;
}
public function index()
{
//1.使用面向过程方式实现树层 (淘汰)
$one = \DB::table('types')->where('pid',0)->get();
foreach ($one as $value){
$value->zi = \DB::table('types')->where('pid',$value->id)->get();
}
foreach ($one as $value){
foreach ($value->zi as $v){
$v->zi = \DB::table('types')->where('pid',$v->id)->get();
}
}
//2.使用递归实现数据格式化 (不建议使用，对数据库压力较大)
$arr = $this->data();

//3.递归实现数据格式化 ，优化2
$data = \DB::table('types')->get();
$arr = $this->data1($data,$pid=0);
//实现树形结构
$data = \DB::select('select types.*,concat(path,id) p from types order by p');
//查询数据
//        $data = \DB::table('types')->orderBy('sort','desc')->get();
return view('admin.types.index',['data'=>$data]);
}