title: Rolling 30 days of data from Big Query
body: <p>Suppose I have this query: </p>
  
  <pre><code>SELECT ga_channelGrouping, ga_sourceMedium,ga_campaign, SUM(ga_sessions) as sessions,
  SUM(ga_sessionDuration)/SUM(ga_sessions) as avg_sessionDuration, 
  SUM(ga_users)as Users, SUM(ga_newUsers)as New_Users, SUM(ga_bounces)/SUM(ga_sessions) 
  AS ga_bounceRate, SUM(ga_pageviews)/SUM(ga_sessions)as pageViews_per_sessions, 
  SUM( ga_transactions)/SUM(ga_sessions) AS ga_conversionRate 
  
  
  FROM db.table 
  
  group by ga_channelGrouping, ga_sourceMedium,ga_campaign
  </code></pre>
  
  <p>How do I find rolling 30 days of data from Big Query. My <code>DATE</code> column value is of this format: <code>2018-06-19 11:00:00 UTC</code></p>