title: percentage calculation for each row in hive
body: <p>i have got a table in hive with the following schema 
  (diference int,count_value int) 
  The values are
  5   2,
  30  1,
  90  1,
  100 1</p>
  
  <p>Now i want to find percentage of each count_value with sum of count_value. Something like count_value/sum(count_value) for each row. Can anybody please help. Thanks in advance</p>