title: Getting all unique values between two columns in mysql
body: <p>I have a mysql table that has two fields that store the same type of information. I want to retrieve all unique values in those two fields.</p>
  
  <p>If it were just one field I could do: </p>
  
  <pre><code>SELECT distinct FIELD1 FROM table
  </code></pre>
  
  <p>How can I get all unique values from FIELD1 and FIELD2</p>
  
  <p><strong>Clarification</strong>: 
  I don't mean unique pairs.</p>
  
  <p>Say field1 contains 1,13,5,25,13,8
  and field2 contains 6,10,1,30,13</p>
  
  <p>I want a query that returns 1,13,5,25,8,6,10,30</p>