title: Returning rows based on sum of column
body: <p>I'm trying to retrieve a subset of data based on the sum of a column.  The goal is a script to release backordered items.  Say we have 100 BO products and get 50 in stock.  I'd like to update the oldest orders where the sum of order qty &lt; 50.  So something like: </p>
  
  <p>Sample Schema:</p>
  
  <pre><code>Orders Table:
  order_id, order_date
  
  order_products Table:
  order_product_id, order_id, product_id, product_status, ordered_quantity
  
  
  select * from products 
  where products_id=1234 
  and status=1 
  and sum(products_qty) &lt; 50;   
  </code></pre>
  
  <p>Where sum(products_qty) is the total returned qty, not just for the individual row. Not sure if this is possible with a single query or even a subquery, but thought I would ask the experts here first.  I'm trying to avoid returning all the rows and then manually count up till I reach the limit.</p>