title: mysql SELECT WHERE and SELECT again
body: <p>I have two tables Customers and Customer_orders. I'm trying to SELECT customer's order by using Customer_ID from Customer table. </p>
  
  <pre><code>SELECT * FROM Customer_orders WHERE Customer_ID = SELECT ID FROM Customers WHERE Customer_name = 'John Doe'
  </code></pre>
  
  <p>This code does not work. How do I do this?</p>