title: how to find min max avg from dynamo db
body: <p>I am working in plotting the graph from dynamodb data.I need to plot max min avg of dynamo db records.
  Example:-</p>
  
  <pre><code>[{
   Time:"yyyy-mm-dd hr:min:sec",
   key:value
   },
  {
  Time:"yyyy-mm-dd hr:min:sec",
  key:value
  }]
  </code></pre>
  
  <p>Help to find the max,min,avg of key based on Date String</p>