Won't Update Table?

[wxdqz]

The code below is what I use to update my table. Although, if I change the value in the form, and click update, it does the sql with no error, but when I look it has not been changed.

What is going on here?

This is my code:
$sql = "UPDATE $table_name
SET
fname = '$fname',
lname = '$lname',
email = '$email',
title = '$title',
code_desc = '$code_desc',
code_notes = '$code_notes',
code = '$code',
date_added = '$date_added'
WHERE id = '$id'
";