title: oracle SQL convert some columns to rows
body: <p>I have a table like below and i am trying to find the best query to convert only the months to rows.</p>
  
  <pre><code>**CODE  YEAR    JAN FEB MAR**
  aa      2017    1   2   3
  bb      2017    4   5   6
  cc      2017    7   8   9
  </code></pre>
  
  <p>So that the result is:</p>
  
  <pre><code>**CODE  YEAR    MONTH   value**
  aa      2017    JAN     1
  aa      2017    FEB     2
  aa      2017    MAR     3
  bb      2017    JAN     4
  bb      2017    FEB     5
  bb      2017    MAR     6
  cc      2017    JAN     7
  cc      2017    FEB     8
  cc      2017    MAR     9
  </code></pre>
  
  <p>Could you please help</p>