title: Grafana elasticsearch - How to do arithmetic operation on two elastic queries result
body: <p>I am drawing timeline link chart to get avg post counts per active users. I have following query result:
  A: total active users [unique] count per hour
  B. total posts added by all users per hour
  I want to draw line chart for avg posts per active users for that hour [B/A].</p>
  
  <p>How I can divide result of B by A for each hour.
  <a href="https://i.stack.imgur.com/ZYnsW.png" rel="nofollow noreferrer"><img src="https://i.stack.imgur.com/ZYnsW.png" alt="Refer screenshot for two line charts for A &amp; B I want to draw another line for B/A"></a></p>