I have a page on my site where I can optionaly filter by certain fields (order by filesize or file category), but I am implementing a shopping cart type of idea where users can submit an order. As administrators, my coworkers and I need to be able to filter orders by their contents. For example: View all orders for "Jack and the Beanstalk," where an order may have Jack and the Beanstalk and other items. I have an order table that keeps track of the order_id, the date, the status, etc. I also have an order_lineitem table that is the contents of the order. This has a one-to-many structure (without foreign keys because it is mysql). I was baffled as to how to filter the orders by the item_id that appears in the order_lineitem table. I just came up with this, but I'm not sure how the mysql_queries will handle an array. Do I have to do some extensive regular expression management here to get this to work, or will it accept an array? <?php if (isset($_POST['showid'])) $showid = $_POST['showid']; $subSQL = "SELECT order_id FROM afy_show_lineitem WHERE show_id = {$_POST['showid']};"; $subResult = mysql_query($subSQL); $where = "WHERE"; $extQuery = 'order_id = {$subResult}'; } $resultOrders = mysql_query("SELECT * FROM afy_order {$where} {$extQuery};") or die(mysql_error("Could not query the database!")); ?>