title: How to get the largest value from list of objects in mongodb
body: <p>I have a mongo document:</p>
  
  <pre class="lang-js prettyprint-override"><code>"apps" : {
      "a" : {
          "last_login" : ISODate("2013-08-07T10:18:39.371Z")
      },
      "b" : {
          "last_login" : ISODate("2013-08-21T09:53:10.769Z")
      },
      "c" : {
          "last_login" : ISODate("2013-08-30T09:53:10.769Z")
      },
  }
  </code></pre>
  
  <p>I want to get the highest last_login value? How do I do it?</p>