title: how to convert columns into rows in HIVE
body: <p>I have a table in HIVE which looks like this</p>
  
  <pre><code>cust_1,month_1, f1,f2,f3 
  cust_1,month_2, f2,f3,f4   
  cust_2,month_1, f1,f5,f4
  </code></pre>
  
  <p>I would like to convert it in the following format</p>
  
  <pre><code>cust_1,month_1, f1
  cust_1,month_1, f2   
  cust_1,month_1, f3
  </code></pre>
  
  <p>....</p>
  
  <p>How that is possible in HIVE? </p>