[MySql query to compare dates php]

Taking the Column Names out of the quotes doesn't work either

 

Also I'm new to PHP, how would I format this in PDO?

[MySql query to compare dates php]

I'm designing a rental service and am working on a query to see if an item is available in a certain date range

So far my query is as follows

$q = "SELECT SUM(quantity) AS total FROM orders, order_details WHERE orders.order_id = order_details.order_id";
        $q .= " AND equip_ID =".$item['id'];
        $q .= " AND  'start_date' > '".$start_date."'";

$result = $db->query($q);
$row = mysqli_fetch_assoc($result);
$sum = $row['total'];

Say for instance $start_date = 2021-03-03 the output of $q would be 

SELECT SUM(quantity) AS total FROM orders, order_details WHERE orders.order_id = order_details.order_id AND equip_ID =12 AND  'start_date' > '2021-03-03'

This does not work but if i manually insert $q into my mysql database it works.

It comes up with the error shown below when I submit it from php, but not when I do directly into mysql

You have an error in your SQL syntax; check the manual that corresponds to your MariaDB server version for the right syntax to use near ''start_date' > '2021-03-03'' at line 1

When I try hard-coding a date in I get the same error. Whats confusing is it works when I directly put it into mysql