title: mongodb subelement querying
body: <p>here is the example</p>
  
  <pre><code>&gt; db.test.insert({ name: 'test', values: [ { check: true }, { check: false } ] })
  &gt; db.find({ values.check: true })[0]
  </code></pre>
  
  <p>so I get both true and false <code>check</code>:</p>
  
  <pre><code>{
          "_id" : ObjectId("50e22046dc278908f3a38a8e"),
          "name" : "test",
          "values" : [
                  {
                          "check" : true
                  },
                  {
                          "check" : false
                  }
          ]
  }
  </code></pre>
  
  <p>and I want to get this:</p>
  
  <pre><code>{
          "_id" : ObjectId("50e22046dc278908f3a38a8e"),
          "name" : "test",
          "values" : [
                  {
                          "check" : true
                  }
          ]
  }
  </code></pre>
  
  <p>is there any filter commands for this?</p>