Updating all columns that has same title but have different ids - php

Question

I have a table named collection and has columns like title,author,edition,volume, etc. Now, i want to be able to update all columns that has been edited with the same title but have different ids.
here is my example code
$con=mysqli_connect("localhost","root","","library03");
$check="SELECT * FROM collection WHERE title = '$_POST[title]'";
$rs = mysqli_query($con,$check);
$data = mysqli_fetch_array($rs, MYSQLI_NUM);
if($data[0] > 1) {
for($i=0;$i<=COUNT($data);$i++){
$sql="UPDATE collection SET author = '$new_author' WHERE title = '$_POST[title]'";
$sql_connect = mysqli_query($sql);
And these are under my $_POST
$collection = Collection::find_by_id($_POST['id']);
$collection->date_received = $_POST['date_received'];
$collection->title = $_POST['title'];
$collection->author = $_POST['author'];
$collection->edition = $_POST['edition'];
$collection->volume = $_POST['volume'];
$collection->pages = $_POST['pages'];
$collection->cost = $_POST['cost'];
$collection->publisher = $_POST['publisher'];
$collection->pub_year = $_POST['pub_year'];
$collection->remarks = $_POST['remarks'];
$collection->call_number = $_POST['call_number'];
$collection->col_copy = $_POST['col_copy'];