title: Syntax error when querying in BigQuery, only difference is "lookup" as an alias in query
body: <p>The following query does not work, although it seems a valid syntax.</p>
  
  <pre><code>SELECT
    *
  FROM
  
  (
  SELECT 
    fullvisitorid
  FROM [93207306.ga_sessions_20150823]
  ) as lookup
  
  LIMIT 1000
  </code></pre>
  
  <p>However the following query works, when I changed <code>lookup</code> to something else.</p>
  
  <pre><code>SELECT
    *
  FROM
  
  (
  SELECT 
    fullvisitorid
  FROM [93207306.ga_sessions_20150823]
  ) as lookuptable
  
  LIMIT 1000
  </code></pre>
  
  <p>Is there any explanation of this behavior? Thanks.</p>