title: BigQuery fetching this week and last week data
body: <p>Suppose I have a query:</p>
  
  <pre><code>SELECT ga_channelGrouping, ga_sourceMedium, SUM(ga_sessionDuration)/SUM(ga_sessions) as avg_sessionDuration 
  
  FROM database.table 
  
  group by ga_channelGrouping, ga_sourceMedium
  </code></pre>
  
  <p>. </p>
  
  <p>How do I select <em>last week</em> and <em>this week's</em> data from <code>BigQuery</code> if I have a <code>DATE</code> column which looks like this <code>2018-06-19 11:00:00 UTC</code>.</p>