title: Cannot have a qualifier in the select list while performing a JOIN w/ USING keyword
body: <p>I am looking at a practice test that doesn't have explanations about the correct answers. The question I'm confused about basically asks why the following SQL statement can never work:</p>
  
  <pre><code>SELECT oi.order_id, product_jd, order_date
  FROM order_items oi JOIN orders o
  USING(order_id);
  </code></pre>
  
  <p>The answer it gave was: "The statement would not execute because the column part of the USING clause cannot have a qualifier in the SELECT list"</p>
  
  <p>Can someone elaborate on this? I am pretty stumped.</p>