php 数据 varchar 的 substr 函数

Question

我有问题，我想输入数据发票号码，当我在我的计算机中尝试使用 phpmyadmin 版本 5.6.16 时，它可以工作，但我上传到 cpanel phpmyadmin v 5.5 它不工作。

V 5.6.16 中的结果:

- INV0001
- INV0002
- INV0003

Cpanel/Hosting 中的结果。 V 5.5:

- INV0001
- INV0001
- INV0001

重复了，怎么解决？先谢谢了。

<?php
  $query = "SELECT max(invoice) AS invoice FROM orders";
  $hasil = mysql_query($query);
  $data  = @mysql_fetch_array($hasil);
  $lastinv = $data['invoice'];
  $nextInv= (int) substr($lastinv, 3, 4);
  $nextInv++;
  $char = "INV";
  $newInvoice = $char .  sprintf("%04s", $nextInv);
?>

Answer 1

您可以尝试以下代码以避免重复记录:

$query = "SELECT max(invoice) AS invoice FROM orders";
$hasil = mysql_query($query);
$data  = @mysql_fetch_array($hasil);
$lastinv = $data['invoice'];
$nextInv= (int) substr($lastinv, 3, 4);
$nextInv++;
$char = "INV";

$i = 1;
while(true) // eliminating duplicacy
{
    $newInvoice = $char .  sprintf("%04s", $nextInv);

    $query = "SELECT * FROM orders where invoice = ".$newInvoice;
    $hasil = mysql_query($query);
    $data  = @mysql_fetch_array($hasil);
    if(empty($data))
        break;
    $i++;
}