title: BigQuery Standard SQL, get max value from json array
body: <p>I have a BigQuery column which contains STRING values like</p>
  <pre><code>col1
  [{&quot;a&quot;:1,&quot;b&quot;:2},{&quot;a&quot;:2,&quot;b&quot;:3}]
  [{&quot;a&quot;:3,&quot;b&quot;:4},{&quot;a&quot;:5,&quot;b&quot;:6}]
  </code></pre>
  <p>Now when doing a SELECT for each I want to get just the max. value of &quot;a&quot; in each json array for example here I would want the output of the SELECT on the table to be</p>
  <pre><code>2
  5
  </code></pre>
  <p>Any ideas please?  Thanks!</p>