Increment issue while creating a unique order number - php

Question

I am creating order numbers like this:
ACC4_11082018_1
ACC4_11082018_2
ACC4_11082018_3
ACC4_11082018_4
ACC4_11082018_5
.
.
.
.
etc.
I am getting an issue with incrementing the last digit.
I tried the code
date_default_timezone_set('Asia/Kolkata');
$myDate = date('dmY');
$get_id=4;
$i=1;
echo $order_no='ACC'.$get_id.'_'.$myDate.'_'.$i;
$i++;
Would you help me out with this?

Answer 1

I have no clue where you will be using this code/logic but this will give you infinity:
date_default_timezone_set('Asia/Kolkata');
$myDate = date('dmY');
$get_id=4;
$i=0;
while( ++$i )
{
echo $order_no='ACC'.$get_id.'_'.$myDate.'_'.$i;
// echo '<br>'; // uncomment this if you want it to look normal in your browser
}
Or if infinity is not desired then:
date_default_timezone_set('Asia/Kolkata');
$myDate = date('dmY');
$get_id=4;
$i=0;
// stop after 1,000
while( ++$i <= 1000 )
{
echo $order_no='ACC'.$get_id.'_'.$myDate.'_'.$i;
// echo '<br>'; // uncomment this if you want it to look normal in your browser
}

Answer 2

If you really want to generate a unique order number for anything:
you have to check that order number if already exists in database or note
/* --------------------------- New order number --------------------------- */
$check_for_order = $con->query("SELECT `order_no` FROM `table` ORDER BY `id` DESC LIMIT 1");
if($check_for_order->num_rows==1){
$row=mysqli_fetch_array($check_for_order);
$previous_order = trim($row['order_no']);
$new_order = $previous_order + 1;
$insert_order_number = $con->query("INSERT INTO `table`(`order_no`) VALUES ('{$new_order}')");
}else{
$previous_order = 1;
$on_date = date("Ymdhis"); // or you can use time() instead
$new_order = $on_date.$previous_order;
$insert_order_number = $con->query("INSERT INTO `table`(`order_no`) VALUES ('{$new_order}')");
}
/* ----------------------- New Order Number here -------------------------- */
$order_no = $new_order;