title: extract array of arrays in presto
body: <p>I have a table in Athena (presto) with just one column named <code>individuals</code> and this is the type of then column:</p>
  <pre><code>array(row(individual_id varchar, ids array(row(type varchar, value varchar, score integer))))
  </code></pre>
  <p>I want to extract <code>value</code> from inside the <code>ids</code> and return them as a new array. As an example:</p>
  <pre><code>[{individual_id=B1Q, ids=[{type=H, value=efd3, score=1}, {type=K, value=NpS, score=1}]}, {individual_id=D6n, ids=[{type=A, value=178, score=6}, {type=K, value=NuHV, score=8}]}]
  </code></pre>
  <p>and I want to return</p>
  <pre><code>ids
  [efd3, NpS, 178, NuHV]
  </code></pre>
  <p>I tried multiple solutions like</p>
  <pre><code>select * from &quot;test&quot;
  CROSS JOIN UNNEST(individuals.ids.value) AS t(i)
  </code></pre>
  <p>but always return</p>
  <pre><code> Expression individuals is not of type ROW
  </code></pre>