我有一个表，我有一个过滤器，目前将按部门过滤（目前只有管理员选项）我想要根据数据库中输入的所有部门生成过滤器选项，这样当新员工是添加了一个新的部门，然后它会自动显示为过滤器中的一个选项。这可能吗？
<?php
if(isset($_GET['aksi']) == 'delete'){
$id = $_GET['id'];
$cek = mysqli_query($db, "SELECT * FROM employees WHERE id='$id'");
if(mysqli_num_rows($cek) == 0){
echo '<div class="alert alert-info alert-dismissable"><button type="button" class="close" data-dismiss="alert" aria-hidden="true">×</button>Data not found</div>';
}else{
$delete = mysqli_query($db, "DELETE FROM employees WHERE id='$id'");
if($delete){
echo '<div class="alert alert-primary alert-dismissable"><button type="button" class="close" data-dismiss="alert" aria-hidden="true">×</button> Employee removed</div>';
}else{
echo '<div class="alert alert-danger alert-dismissable"><button type="button" class="close" data-dismiss="alert" aria-hidden="true">×</button> Employee removal failed</div>';
}
}
}
?>
<form class="form-inline" method="get">
<a href="add.php" title="Add" class="btn btn-primary-add btn"><span class="glyphicon glyphicon-plus" aria-hidden="true"></span></a>
<div class="form-group">
<select name="filter" class="form-control" onchange="form.submit()">
<option value="0">Filter By Department</option>
<?php $filter = (isset($_GET['filter']) ? strtolower($_GET['filter']) : NULL); ?>
<option value="Admin" <?php if($filter == 'Admin'){ echo 'selected'; } ?>>Admin</option>
</select>
</div>
</form>
<br />
<div class="table-responsive">
<table class="table table-striped table-hover">
<tr>
<th>ID</th>
<th></th>
<th>First Name</th>
<th>Last Name</th>
<th>D.O.B</th>
<th>Telephone</th>
<th>E-mail</th>
<th>Job Title</th>
<th>Site</th>
<th>Department</th>
<th>Tools</th>
</tr>
<?php
if($filter){
$sql = mysqli_query($db, "SELECT * FROM employees WHERE department='$filter' ORDER BY last_name ASC");
}else{
$sql = mysqli_query($db, "SELECT * FROM employees ORDER BY last_name ASC");
}
if(mysqli_num_rows($sql) == 0){
echo '<tr><td colspan="8">Data Tidak Ada.</td></tr>';
}else{
$no = 1;
while($row = mysqli_fetch_assoc($sql)){
echo '
<tr>
<td>'.$row['id'].'</td>
<td><a href="details.php?id='.$row['id'].'"><span class="glyphicon glyphicon-user" aria-hidden="true"></span></td>
<td>'.$row['first_name'].'</a></td>
<td>'.$row['last_name'].'</td>
<td>'.$row['dob'].'</td>
<td>'.$row['telephone'].'</td>
<td>'.$row['email'].'</td>
<td>'.$row['job_title'].'</td>
<td>'.$row['site'].'</td>
<td>'.$row['department'].'</td>
<td>
<a href="details.php?id='.$row['id'].'" title="View" class="btn btn-primary-view btn-sm"><span class="glyphicon glyphicon-unchecked" aria-hidden="true"></span></a>
<a href="edit.php?id='.$row['id'].'" title="Edit" class="btn btn-primary btn-sm"><span class="glyphicon glyphicon-edit" aria-hidden="true"></span></a>
<a href="password.php?id='.$row['id'].'" title="Change Password" data-placement="bottom" data-toggle="tooltip" class="btn btn-warning btn-sm"><span class="glyphicon glyphicon-refresh" aria-hidden="true"></span></a>
<a href="index.php?aksi=delete&id='.$row['id'].'" title="Delete" onclick="return confirm(\'Are you sure you want to delete '.$row['first_name'].'?\')" class="btn btn-danger btn-sm"><span class="glyphicon glyphicon-trash" aria-hidden="true"></span></a>
</td>
</tr>
';
$no++;
}
}
?>