title: If data exists, else... using Oracle SQL?
body: <p>I have two queries at the moment, returning the same data, I want the second query to run if the first returns no results, here's the basic idea of my PHP right now:</p>
  
  <pre><code>Run Query1
  If Query1 returns a result
      Enter data into array
  Else 
      Run Query2
      Enter data into array
  </code></pre>
  
  <p>What I'm wondering, is can I do that exclusively using Oracle SQL? So it'd just run a single query to the database, do a quick check of the first statement, and if no results are found run the second one?</p>
  
  <p>Thanks</p>