title: how to read a complex type array<string> on impala or hive?
body: <p>I try to read a complex type on hive </p>
  
  <pre><code>dog.owners (array&lt;string&gt;)
  </code></pre>
  
  <p>with the following query</p>
  
  <pre><code>select dog_id, concat_ws(',',collect_set(owners)) as owners 
  from dog 
  group by dog_id
  </code></pre>
  
  <p>but i receive the following error</p>
  
  <blockquote>
    <p><code>Argument 2 of function CONCAT_WS must be "string or array&lt;string&gt;", but "array&lt;array&lt;string&gt;&gt;" was found.</code></p>
  </blockquote>
  
  <p>Looks like there is a data type mismatch. I tried to create the column owners as an <code>array&lt;array&lt;string&gt;&gt;</code> but i still get the same error.
  Is there a way to read that column on hive or impala? </p>