title: how to delete duplicated rows in db2 when all the fields are duplicated?
body: <p>I have a table:</p>
  
  <pre><code> A
   1
   1
   1
   2
  </code></pre>
  
  <p>And I want to be transformed to</p>
  
  <pre><code> A
   1
   2
  </code></pre>
  
  <p>How I might do it?
  thanks</p>