title: simple jq filter has null results
body: <p>I'm using the filter </p>
  
  <pre><code>[.bar_1.baz_a, .bar_1.baz_b, .bar_2.qux_1,.bar_2.qux_2]
  </code></pre>
  
  <p>on the following JSON and it's returning four nulls instead of two lines each having four elements of nonsense data.  This is my first attempt at a filter, what concept am I not comprehending?</p>
  
  <pre><code>{
    "version": "0.1",
    "foos": [
      {
        "bar_1": {
          "baz_a": 673396201,
          "baz_b": "dfgsfg"
        },
        "bar_2": {
          "qux_1": "ghjhj",
          "qux_2": "Q"
        }
      },
      {
        "bar_1": {
          "baz_a": 674567484,
          "baz_b": "tyutyj"
        },
        "bar_2": {
          "qux_1": "bnmn",
          "qux_2": "Z"
        }
      }
    ]
  }
  </code></pre>