title: How to extract keys in a nested json array object in Presto?
body: <p>I'm using the latest(0.117) Presto and trying to execute <strong>CROSS JOIN UNNEST</strong> with complex JSON array like this.</p>
  
  <pre><code>[{"id": 1, "value":"xxx"}, {"id":2, "value":"yy"}, ...]
  </code></pre>
  
  <p>To do that, first I tried to make an <strong>ARRAY</strong> with the values of <strong>id</strong> by </p>
  
  <pre><code>SELECT CAST(JSON_EXTRACT('[{"id": 1, "value":"xxx"}, {"id":2, "value":"yy"}]', '$..id') AS ARRAY&lt;BIGINT&gt;)
  </code></pre>
  
  <p>but it doesn't work.</p>
  
  <p>What is the best JSON Path to extract the values of <strong>id</strong>?</p>