title: select all orders where order details state is complete
body: <pre><code>orders:
  id state
  
  order_details:
  id order_id state
  
  order has_many order_details
  </code></pre>
  <p>i need to select all orders with its order details state is complete?
  i mean if an order have 5 order details, its order details must be complete.</p>
  <p>and How to implement this in elixir ecto query?</p>