title: Oracle UNION different columns
body: <p>I have two tables looking something like:</p>
  
  <pre><code>TABLE_1
  COL_A (int), COL_B (float), COL_C (float)
  
  
  TABLE_2
  COL_A (int), COL_B (float)
  </code></pre>
  
  <p>My query is using a UNION to put the results of these tables together, but where TABLE_2 doesn't have a COL_C, I'm looking to put something like '0'.
  But I just get a <strong>'ORA-00918: column ambiguously defined'</strong> error</p>
  
  <p>How can I get around this?</p>