title: Find unique row compared to other entries in table
body: <p>I have following table:</p>
  
  <pre><code>+-ID-+-USER--+--VALUE--+
  |1   |'userA'|'MOV-AAA'|
  |2   |'userB'|'MOV-AAA'|
  |3   |'userB'|'MOV-BBB'|
  |4   |'userC'|'MOV-AAA'|
  |5   |'userC'|'MOV-BBB'|
  |6   |'userD'|'MOV-EEE'|
  +----+-------+---------+
  </code></pre>
  
  <p>And I would like to find now ALL unique VALUE compared to 2 user. Like userA and userB. While comparing userA and userB I would expect MOV-BBB.</p>
  
  <p>At the moment I have this query:</p>
  
  <pre><code>SELECT A.userName, A.value
  FROM testTable A
  WHERE EXISTS
         (SELECT B.userName, B.value
          FROM testTable B
          WHERE B.value &lt; A.value)
  </code></pre>
  
  <p>And receive this result:</p>
  
  <pre><code>userName    value
  userB       MOV-BBB
  userC       MOV-BBB
  userD       MOV-EEE
  </code></pre>
  
  <p>Thank you</p>