PHP 'while' loop or 'if' statement in another 'while' loop?

Question

I have a PHP/MySQL query that returns to an HTML table, and I'm stuck on a part where I need to make a second while loop in that query. I'm not sure where to go from here. I've tried a couple of different ways.

I want it to loop and give me the first set of data, then use the "Order_ID" and get a second set of data and put that second set in the first loop, then do it again.

Here's what I have...

<?php
    $arrayLC = array();

    $OrdersToShip = mysql_query("
        SELECT *
        FROM Orders o
        WHERE o.LotCoded = 0 ORDER BY o.Order_ID");

    if ($OrdersToShip) {
        while ($info = mysql_fetch_array($OrdersToShip))
        {
            $Order_ID = $info['Order_ID'];
            $Customer_ID = $info['Customer_ID'];
            $OrderDate = $info['OrderDate'];

            $lotCodes = mysql_query("SELECT lotCode, Qty FROM `OrdersLotCodes` WHERE `Order_ID` = '".$Order_ID."'");

            if($lotCodes) {
                while ($info = mysql_fetch_array($lotCodes))
                {
                    $lotCode = $info['lotCode'];
                    $Qty = $info['Qty'];
                    array_push($arrayLC, $lotCode, $Qty);
                }
            }

            echo '<tr class="OLine">
                 <td><input type="button" class="button viewThis" value="VIEW"></td>
                 <td>'.$Order_ID.'</td>
                 <td>'.$Customer_ID.'</td>
                 <td>'.$OrderDate.'</td>
                 <td>'.print_r($arrayLC).'</td>
                 </tr>';
        }
    }
    else {
        echo "encountered an error.".mysql_error();
    }
    mysql_close($conn);
?>

What am I missing? What should I do?

::EDIT::

I've changed the mysql_query to:

SELECT o.Order_ID, o.Customer_ID, o.OrderDate, olc.lotCode, olc.qty
FROM Orders o
LEFT JOIN OrdersLotCodes olc ON o.Order_ID = olc.Order_ID
WHERE o.LotCoded = 0 ORDER BY o.Order_ID

Now, how would I take the output with the OrderLotCodes and put them into an array to be printed in the table? How would I put them in an array then bring the related one by Order_ID?

Jon · Accepted Answer · 2012-03-26 16:56:36Z

4

One problem that I can see is that you are not resetting $arrayLC inside the outer while loop; therefore, the codes from each order get appended to those of the previous one, ad infinitum.

if($OrdersToShip) {
    while ($info = mysql_fetch_array($OrdersToShip)) {

    $arrayLC = array(); // SHOULD BE IN HERE!

Apart from that, when you get this code working you should think about the fact that for N orders, this code executes N + 1 queries (1 to get the orders and one per order to get the items). This is a really inefficient way to do things considering that you can retrieve the same information with just one query if you perform a left outer join. So your next stop should be reading up on SQL joins and how they can help you retrieve associated data.

answered Mar 26, 2012 at 16:56

Jon

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