Pass certain table cell values to SQL update query - php

Question

I feel stuck with a bit unusual situation for me up until now ... I constructed a HTML table that shows quantities from different locations by reading and rows from SQL DB into a $locations variable that is essentially an array - here's the code:
while ($location = mssql_fetch_array($locations)){
echo"
<tr>
<td style='text-align:center; padding-left: 2px; padding-right: 2px'>$location[1]</td>
<td style='text-align:center; padding-left: 2px; padding-right: 2px'>$location[2]</td>
<td width='50' style='text-align:center; padding-left: 2px; padding-right: 2px'><input type='number' style='border:none;text-align:center;' class='input' name='qty_to_add[]' type='text' value='' min='1' max='999'></td>
</tr>";
};
But the real problem is how do I read only cells in the third column to the right, that have values imputed and pass only those to an update query that will further update only those rows that contain locations POL_12 (15 pcs + 5 more) and POL_54 (30 pcs + 7 more)?
I need to do this in a procedural way, since I am not yet familiar with OOP and PDO (but I am striving to learn it soon) :/
Please advise, all suggestions are welcome! Thank Y'all!

Answer 1

In this scenario, following Barmar's advice (because it seemed most familiar to me in this moment) - using hidden fields in a form combined with for loop worked like a charm!
<form method="post" enctype="multipart/form-data">
<table style="width:100%" border="2">
<tr>
<th style="text-align:center; padding-left: 2px; padding-right: 2px">Location</th>
<th style="text-align:center; padding-left: 2px; padding-right: 2px">Qty</th>
<th style="text-align:center; padding-left: 2px; padding-right: 2px">Qty to add</th>
</tr>
<?php
$locations = mssql_query("my query for reading item name, location and quantity per location ");
while ($location = mssql_fetch_array($locations))
{
echo"
<tr>
<input style='border:none;text-align:center;' class='input' name='location_id[]' type='hidden' value='$location[0]'>
<input style='border:none;text-align:center;' class='input' name='item_id[]' type='hidden' value='$location[3]'>
<td style='text-align:center; padding-left: 2px; padding-right: 2px'>$location[1]</td>
<td width='2' style='text-align:center; padding-left: 2px; padding-right: 2px'><input type='number' style='border:none;text-align:center;' class='input' name='current_qty[]' type='text' value='";if (!isset($location[2])) {echo "0";} else {echo $location[2];}; echo "'></td>
<td width='50' style='text-align:center; padding-left: 2px; padding-right: 2px'><input type='number' style='border:none;text-align:center;' class='input' name='qty_to_add[]' type='text' value='0' min='0' max='999'></td>
</tr>";
};
?>
</table></br>
<input id="post" class="search" name="submit" type="submit" value="POST" style="position: relative"></br>
</form>
<?php
if (isset($_POST['submit']))
{
$location_id = $_POST['location_id'];
$ite_id = $_POST['item_id'];
$curr_qty = $_POST['current_qty'];
$added_qty = $_POST['qty_to_add'];
$rowCount = count($_POST['location_id']);
for ($i = 0; $i < $rowCount; $i++)
{
if ($added_qty > 0)
{
$query = mssql_query("update [my-table-name] set qty_per_location = cast('$curr_qty[$i]' as decimal (5,2)) + cast('$added_qty[$i]' as decimal (5,2)) where item_id = $item_id[$i] and item_location_id = $location_id[$i]");
echo "<br/><br/><span>Data inserted to DB successfully!</span>";
}
}
}
?>
I don't want to sound disrespectful to others, that suggested possible solutions - I chose this solution merely because it was understandable for my current novice level of knowledge! Instead a big shoutout to all that sacrificed a lil' bit their time to contribute. Thank y'all!