title: Unable to use CAST AS RECORD on SELECT
body: <p>I have a simple table with 2 columns: Col1 and Col2</p>
  
  <pre><code>sh-3.2# ./bq show --schema dataset.Test
  [{"type":"STRING","name":"Col1","mode":"NULLABLE"},{"type":"STRING","name":"Col2","mode":"NULLABLE"}]
  </code></pre>
  
  <p>This Query works fine</p>
  
  <pre><code>SELECT * EXCEPT (Col2) , CAST(Col2 AS NUMERIC) AS Col2 FROM `project.dataset.Test` LIMIT 1000
  </code></pre>
  
  <p>This Query returns an error</p>
  
  <pre><code>SELECT * EXCEPT (Col2) , CAST(Col2 AS RECORD) AS Col2 FROM `project.dataset.Test` LIMIT 1000
  </code></pre>
  
  <p>Any ideas why?</p>
  
  <p>I'm trying to use the keyword RECORD as appeared in the WebUI</p>
  
  <p><a href="https://i.stack.imgur.com/qQ3ED.png" rel="nofollow noreferrer"><img src="https://i.stack.imgur.com/qQ3ED.png" alt="enter image description here"></a></p>