<?php

//    父子类
     function treeLevel(array $data, int $pid = 0, string $html = '--', int $level = 0)
    {
        static $arr = [];
        foreach ($data as $val) {
            if ($pid == $val['pid']) {
                // 重复一个字符多少次
                $val['html'] = str_repeat($html, $level * 2);
                $val['level'] = $level + 1;
                $arr[] = $val;
                $this->treeLevel($data, $val['id'], $html, $val['level']);
            }
        }
        return $arr;
    }

//    树状多层级
   function subTree(array $data, int $pid = 0)
    {
        $arr = [];
        foreach ($data as $val) {
            if ($pid == $val['pid']) {
                $val['sub'] = $this->subTree($data, $val['id']);
                $arr[] = $val;
            }
        }
        return $arr;
    }
//    树状多层级优化版
    function subTree(array $data,string $key = 'unid',string $child = 'child',$parent = '',$pid = 0){
        $arr = [];
        foreach ($data as $val) {
            if ($pid == $val[$parent]) {
                $val[$child] = subTree($data, $key,$child,$parent,$val[$key]);
                $arr[] = $val;
            }
        }
        return $arr;
    }
    // 引用解决树状多层级
    public  function getTree(array $data,string $key='id',string $child = 'children',string $parent = '',$pid = 0){
        $array = [];
        foreach($data as $value){
            $array[$value[$key]] = $value;
        }
        foreach($array as $k=>$v){
            if(isset($array[$v[$parent]])){
                $array[$v[$parent]][$child][] = &$array[$k];
            }else{
                $reback[] = &$array[$k];
            }
        }
        return $reback;
    }
    //毫秒级时间戳
    function getMillisecond() {
        list($t1, $t2) = explode(' ', microtime());
        return (float)sprintf('%.0f',(floatval($t1)+floatval($t2))*1000);
    }

    // mysql批量更新 相当与 id = 1 时 inventory  = 1 id = 2时 inventory = 2 $update_unid 需要更新的主键
    UPDATE pro_goods_spec_price 
         SET inventory = CASE unid 
         //这是占位符 格式是 WHEN 1 THEN 1 WHEN 2 THEN 2
            %s
         END,
         SET sales = CASE unid
            %s
         END
    WHERE unid IN $update_unid