以下是我在做電商系統用的訂單號生成函數 ：：
/**
 * 訂單序列生成 16位
 * $type支付/提取類型
 *  $usertype用戶類型
 *  $oid 訂單自增長
 */
public function getOrderNo($type,$usertype,$oid)
{
    $password = array(0 => array(0, 5, 1, 2, 6, 4, 3, 8, 9, 7),
        1 => array(9, 8, 7, 6, 5, 4, 3, 2, 1, 0),
        2 => array(4, 3, 2, 1, 0, 5, 6, 7, 8, 9),
        3 => array(5, 6, 7, 8, 9, 0, 1, 2, 3, 4),
        4 => array(9, 0, 8, 1, 7, 3, 6, 4, 5, 2),
        5 => array(7, 2, 6, 4, 5, 1, 8, 0, 9, 3),
        6 => array(6, 7, 8, 9, 5, 4, 3, 2, 1, 0),
        7 => array(5, 9, 7, 8, 3, 4, 2, 6, 1, 0),
    );
    $ret = date(‘ymd‘) . $type . $usertype;
    $oid = str_pad($oid, 8, "0", STR_PAD_LEFT);
    for ($i = 0; $i < 8; $i++) {
        $oid[$i] = $password[$i][$oid[$i]];
    }
    $ret .= $oid;
    return $ret;

}

訂單號生成函數