title: BigQuery UPDATE multiple nested columns
body: <p>I would like to understand the principle of how to update a BigQuery Nested table.</p>
  
  <p>For example, with have a table:</p>
  
  <pre><code>ID   GROSS   OL.ID  OL.GROSS   PL.ID   PL.GROSS
  1    100     12     200        34      454
               34     465        56      5667
               67     7876    
  </code></pre>
  
  <p>And I would like to update the gross value for the main, OL. and PL. to any other value</p>
  
  <p>What is the way to do it?</p>