title: Querying mongodb
body: <p>I have a collection of emails in MongoDB with a field containing an array of json. </p>
  
  <p>How can knowing the sender and the receiver, how can I find all the emails exchanged between the two people ? I need to do something like</p>
  
  <p><code>db.email.find({"from": i.st20@gmail.com", "tos":"ron@gmail.com")</code> </p>
  
  <p>but I cant find the right way to write this query :(</p>
  
  <pre><code>&gt; db.emails.findOne()
  {
  
      "from" : {
          "real_name" : "it",
          "address" : "i.st20@gmail.com"
      },
      "tos" : [
          {
              "real_name" : null,
              "address" : "ron@gmail.com"
          }
      ],
  
  }
  </code></pre>