Href Modal not working - php

Question

I am new in PHP. My href modal doesn't work perfectly.
I am working on a database search with edit items function.
On initial load of the datatable, the edit anchor tag should return field values in
the modal form.
However it doesn't seem to work. When I clicked the icon it didn't do anything.
I am thinking maybe there is conflict between my search queries and div ids?
Here is my code:
My code for the search query:
$sql_result = mysql_query ($sql, $conn ) or die ( "Could not execute SQL
query" .$sql);
if (mysql_num_rows($sql_result)>0) {
while ($row = mysql_fetch_assoc($sql_result)) {
$project=$row['Project'];
$id=$row['ID'];
$discipline=$row['Discipline'];
$area_code=$row['Area_Code'];
$drawingnumber=$row['Drawing_Number'];
$documenttitle=$row['Document_Title'];
$approveddate=$row['Approved_Date'];
$revnumber=$row['Revision'];
$status=$row['Status'];
$transnumber=$row['Transmittal_No'];
//table row
<tr>
<td><?php echo $project; ?></td>
<td><?php echo $discipline; ?></td>
<td><?php echo $area_code ;?></td>
<td><?php echo $drawingnumber ;?></td>
<td><?php echo $documenttitle; ?></td>
<td><?php echo $approveddate; ?></td>
<td><?php echo $revnumber; ?></td>
<td><?php echo $status; ?></td>
<td><?php echo $transnumber; ?></td>
<td><?php echo $id; ?></td>
<div class='btn-group' role='group' aria-label='...'>
<td> <button type='button' class='btn btn-warning btn-sm'>Edit<span class='glyphicon glyphicon-edit' aria-hidden='true'></span></button></td>
</div>
</tr>
My href edit Modal:
<div id="edit<?php echo $id; ?>" class="modal fade" role="dialog">
<form method="post" class="form-horizontal" role="form">
<div class="modal-dialog modal-lg">
<!-- Modal content-->
<div class="modal-content">
<div class="modal-header">
<button type="button" class="close" data-dismiss="modal">×</button>
<h4 class="modal-title">Edit Item</h4>
</div>
<div class="modal-body">
<input type="hidden" name="edit_item_id" value="<?php echo $id; ?>">
<div class="form-group">
<label class="control-label col-sm-2" for="discipline">Discipline:</label>
<div class="col-sm-4">
<input type="text" class="form-control" id="discipline" name="discipline" value="<?php echo $id; ?>" required autofocus>
</div>
<label class="control-label col-sm-2" for="area_code">Area Code:</label>
<div class="col-sm-4">
<input type="text" readonly class="form-control" id="area_code" name="area_code" value="<?php echo $area_code;?>" required>
</div>
<label class="control-label col-sm-2" for="drawingnumber">Drawing Number:</label>
<div class="col-sm-4">
<input type="text" class="form-control" id="drawingnumber" name="drawingnumber" value="<?php echo $drawingnumber; ?>" required >
</div>
<label class="control-label col-sm-2" for="documenttitle">Document Title:</label>
<div class="col-sm-4">
<input type="text" class="form-control" id="documenttitle" name="documenttitle" value="<?php echo $documenttitle; ?>" required >
</div>
<label class="control-label col-sm-2" for="approveddate">Approved Date:</label>
<div class="col-sm-4">
<input type="text" class="form-control" id="approveddate" name="approveddate" value="<?php echo $approveddate; ?>" required>
</div>
<label class="control-label col-sm-2" for="revnumber">Revision Number:</label>
<div class="col-sm-4">
<input type="text" class="form-control" id="revnumber" name="revnumber" value="<?php echo $revnumber; ?>" required >
</div>
<label class="control-label col-sm-2" for="status">Status:</label>
<div class="col-sm-4">
<input type="text" class="form-control" id="status" name="status" value="<?php echo $status; ?>" required >
</div>
<label class="control-label col-sm-2" for="transnumber">Transmittal Number:</label>
<div class="col-sm-4">
<input type="text" class="form-control" id="transnumber" name="transnumber" value="<?php echo $transnumber; ?>" required >
</div>
</div>
</div>
</div>
</div>
</form>
</div>