title: Get results based on conditions in other table
body: <p>I have a table </p>
  
  <pre><code>Orders
  
  ID       User
  -----------------
  1        Matt
  2        Chris
  3        John
  </code></pre>
  
  <p>then I have another table</p>
  
  <pre><code>Order_Contact
  
  ID      Order_ID        Type                    Timestamp                   
  -------------------------------------------------------------------
  1       1               Request                 2018-01-01 10:00:00
  2       1               Request                 2018-01-01 10:35:00
  3       1               Response                2018-01-01 11:00:00
  4       1               Request                 2018-01-01 12:00:00
  5       2               Request                 2018-01-01 13:00:00
  6       2               Response                2018-01-01 14:00:00
  </code></pre>
  
  <p>My goal is to create a query that returns all Orders that have "open" contact requests that have no response. One response is enough to satisfy multiple requests. Requests that have no response at later datetime than the request are "open". How could I achieve this?</p>
  
  <p>In the above scenario I would like to return</p>
  
  <pre><code>ID       User
  ----------------
  1        Matt
  </code></pre>