PHP - Mysql Autoincrement Questions

Hi..

I have code for auto increment of JO Number, now it display:
120504001
by using this code:

<?php
  $sql = "SELECT jo_number FROM job_order ORDER BY jo_date DESC LIMIT 1";
        $result = mysql_query($sql, $con);
        
        if (!$result) {
            echo 'failed'; 
            die();
        }
        $total = mysql_num_rows($result);
        if ($total <= 0) {
            $currentSRNum = 1;
             $currentYear  = (int)(date('y'));
            $currentMonth = (int)(date('m'));
            $currentDay = (int)(date('d'));
           
            $currentSRYMD = substr($row['jo_number'], 0, 6);
            $currentYMD = date("ymd");
            if ($currentYMD > $currentSRYMD) 
            {  
                $currentSRNum = 1;
            } 
            else 
            {  
                $currentSRNum += 1;
            }     
             
        } 
        else {
//------------------------------------------------------------------------------------------------------------------
            // Stock Number iteration.... 
            $row = mysql_fetch_assoc($result);
            
            $currentSRNum = (int)(substr($row['jo_number'],0,3));
            
            $currentSRYear  = (int)(substr($row['jo_number'],2,2));
            $currentSRMonth = (int)(substr($row['jo_number'],0,2));
           $currentSRNum = (int)(substr($row['jo_number'],6,4));
            $currentYear  = (int)(date('y'));
            $currentMonth = (int)(date('m'));
            $currentDay = (int)(date('d'));
           
            $currentSRYMD = substr($row['jo_number'], 0, 6);
            $currentYMD = date("ymd");
            if ($currentYMD > $currentSRYMD) 
            {  
                $currentSRNum = 1;
            } 
            else 
            {  
                $currentSRNum += 1;
            }                                           
        }
//------------------------------------------------------------------------------------------------------------------         
        $yearMonth = date('ymd');    
        $currentSR = $currentYMD . sprintf("%03d", $currentSRNum);
?>


now I want it to be:
JO120504001
JO120504002
JO120504003
JO120504004
JO120505001
JO120504002
JO120504003

Any help is highly appreciated.


Thank you so much

I've just learned the basics of MySQL last night and made a simple app (where a user enters a song name, song title, and rating (out of 5) and it displays the list of songs with the highest rated songs first).

So I decided I wanted to make something similar yet slightly more complicated and I'm not sure if I'm on the right track. Basically it's a "flash card" game whe

- The user gets to input their own questions and answers into a simple form, which would then go into an MySQL table with 2 columns, questions and answers
- A new page where the user see's random question, must input an answer, if the answer matches goes to next question otherwise gives error

Now I'm confused as to how to go about making this. I was thinking of making some session variables and then do something along the lines of

Code: [Select]

$display_query = "SELECT * FROM questions";
$display = mysqli_query($connection, $display_query);
     
      while ($row = mysqli_fetch_array($display)) {
$_SESSION['question'] = $row[0];
      }[/syntax]

//and then make some PHP that might do something like this:


            if ($_SESSION['answer'] != $row[1]) {
           echo "error, try again"
} else {
           // I would write something here to grab the next question
}


So am I just completely off the wall with this, how would I make such an app? How would I make it, for example, fetch new questions?

I am creating a new forum software known as Iforum, it will  use php and a database. I just started this yesterday and I all ready have the registration/login system up and working as well as connected to the database.  I have selected the CKeditor for my forum (I was initially thinking of using the TinyMCE editor) I can't seem to figure out how when you click the "Post New Thread Button" How to send the information to the database and then carry the user back to the thread. (I am good with php, html, and CSS but I am not great with databases
Any suggestions?

I've been coding PHP for some time and would consider myself to be at an intermediate level. I can write code to do what I need but it's probably not the best way to do it. I rarely see any code that I am not able to read, understand, or follow. I've created modifications for everything from vBulletin, WordPress, Kayako Support Suit, Magento, and more.

However, I've never really built a strong understanding around OOP. For example, let say you have the following classes:
_main
  -  db
  -  admin
  -  -  modules
  -  -  -  dashboard

How would you share the db connection with the dashboard class? I've been trying to read up on Dependency Injections and Singletons but I haven't found an article that has explained it on a level that I can understand. I get a feeling that most people who use OOP in PHP have a background in Java or C++ and are much more familiar with everything.

Could someone please explain this to me in simple terms or link me to an extremely well explained article that I'd be able to understand without a background in computer science?
Thanks