title: Reverse in SQL by pair
body: <p>I'm very new to SQL and I'd like to do something like this :</p>
  <p>Going from</p>
  <pre><code>12 34 56 78
  </code></pre>
  <p>to</p>
  <pre><code>78 56 34 12
  </code></pre>
  <p>I tried the <code>reverse</code> function, but the result is <code>87 65 43 21</code>.</p>
  <p>Is there a way to do this ? Thank you for reading !</p>