title: Using period "." in Standard SQL in BigQuery
body: <p>BigQuery Standard SQL does not seems to allow period "." in the select statement.  Even a simple query (see below) seems to fail.  This is a big problem for datasets with field names that contain "."  Is there an easy way to avoid this issue?</p>
  
  <p><code>
  select id, time_ts as time.ts
  from `bigquery-public-data.hacker_news.comments` 
  LIMIT 10
  </code></p>
  
  <p>Returns error...
  <code>Error: Syntax error: Unexpected "." at [1:27]</code></p>
  
  <p>This also fails...
  <code>
  select * except(detected_circle.center_x )
  from [bigquery-public-data:eclipse_megamovie.photos_v_0_2] 
  LIMIT 10
  </code></p>