title: How to use the selected period of time in a query?
body: <p>I'm using Grafana with Prometheus and I'd like to build <a href="https://stackoverflow.com/questions/47138461/get-total-requests-in-a-period-of-time">a query</a> that depends on the selected period of time selected in the upper right corner of the screen.</p>
  
  <p>Is there any variable (or something like that) to use in the query field?</p>
  
  <p>In other words, If I select 24hs I'd like to use that data in the query.</p>