title: Get all records in table without field
body: <p>I have a table in <strong>RethinkDB</strong> where I want to retrieve all records where the field <code>single</code> is not set. Because there is no enforced schema some documents stored do not follow the exact same structure.</p>
  
  <p>Example data in table:</p>
  
  <pre><code>{
    "id": "1",
    "age": 27,
    "sex": "female",
    "single": true
  },
  {
    "id": "2",
    "sex": "female",
    "age": 40
  },
  {
    "id": "3",
    "age": 45,
    "sex": "male",
    "single": false
  },
  {
    "id": "4",
    "sex": "male",
    "age": 16
  }
  </code></pre>
  
  <p>I need to write a <strong>ReQL</strong> query that would retrieve records 2 and 4. Any assistance would be greatly appreciated.</p>