title: Building queries in mongodb
body: <p>Hi i´m completely newbie with mongodb, i come from SQL Server, i have the following doubt
  If a have the structure bellow:</p>
  
  <p>Collection: tv</p>
  
  <pre><code>"_id": ObjectId("123456abc"),
  "brand": "Sony",
  "model": "Bravia",
  "price": 1000
  </code></pre>
  
  <p>Collection: tvcomments</p>
  
  <pre><code>"_id": "_id": ObjectId("456789def"),
  "tv": ObjectId("123456abc"),
  "comments": [
           {
             "user": ObjectId("413212eop"),
             "text": "Very nice TV"
           }
  ]
  </code></pre>
  
  <p>I´d like to get tv with their comments, but i don´t find a example to do this, maybe is not possible?</p>