title: Presto query Array of Rows
body: <p>So I have a hive external table with schema looks like this :</p>
  
  <pre><code>{
  .
  .
  `x` string,
  `y` ARRAY&lt;struct&lt;age:string,cId:string,dmt:string&gt;&gt;,
  `z` string
  }
  </code></pre>
  
  <p>So basically I need to query a column(column "y") which is array of nested json,
  I can see data of column "y" from hive, but data in that column seems invisible to presto, even though presto knows schema of this field, like this:</p>
  
  <pre><code>array(row(age varchar,cid varchar,dmt varchar))
  </code></pre>
  
  <p>As you can see presto already knows this field is array of row.</p>
  
  <p>Notes:</p>
  
  <p>1.The table is a hive external table.</p>
  
  <p>2.I get schema of field "y" by using ODBC driver, but data is just all empty, however I can see something like this in hive :
  [{"age":"12","cId":"bx21hdg","dmt":"120"}]</p>
  
  <p>3.Presto queries hivemetastore for schema.</p>
  
  <p>4.Table was stored as parquet format.</p>
  
  <p>So how can I see my data in field "y" please?</p>