title: MongoDB: Find a document by non-existence of a field?
body: <p>Is there a way to specify a condition of "where document doesn't contain field" ?</p>
  
  <p>For example, I want to only find the first of these 2 because it doesn't have the "price" field.</p>
  
  <pre><code>{"fruit":"apple", "color":"red"}
  
  
  {"fruit":"banana", "color":"yellow", "price":"2.00"}
  </code></pre>