I'm assuming hat this script is 'admin.php' as mentioned in the form action (ie the script calls itself, am I right?)
If this is the case, $_POST['id'] will always be blank, unless you happen to to have an office whose id = 'id', as your hidden field is called $id, not "id".
try some simple debugging and add
echo "Query = $query<br>";
before your print statements to see exactly what your query is.
You could also try
foreach($_POST as $k=>$v) {echo "$k = $v<br>";}
to see what was posted
hth