I've been working on this one for little while, but still

Hi, I've been working on this one for little while, but still haven't quite got it to work. I have get_results function working, but can't get_col to work.

The code:

$user_search = esc_attr($_POST['city']);
global $wpdb;
     global $user_search;

     $address_table = $wpdb->prefix . "address_table";
     $query = $wpdb->get_col('SELECT city FROM ' . $address_table . 'WHERE city = ' . $user_search );
print_r($query);

I have this code set up to pull data from a custom table called 'address_table'. The columns are: city, address_id, and, hit_date

I am getting this result: array()

Am I using get_col correctly, and do I have the query set up correctly? Thanks ~