<?php
$yCode=array_merge(range('A', 'Z'),range('a', 'z'),range(0, 9));
$orderSn = $yCode[intval(date('Y')) - 2023];
$orderSn .= $yCode[intval(date('m'))];
$orderSn .= $yCode[intval(date('d'))];
$orderSn .= $yCode[intval(date('H'))];
$orderSn .= $yCode[intval(date('i'))];
$orderSn .= $yCode[intval(date('s'))];
$orderSn .= substr(microtime(), 2, 5)
$orderSn .= sprintf('%02d', mt_rand(0, 99));
echo $orderSn;