Unsupported SubQuery Expression : Correlating expression cannot contain unqualified column references
<p>In <code>Hive</code> the following query fails :</p>

<pre><code>  Select a,b,c from t1 where a in (0,100) AND b in (select b from t2
  where d&gt;2 GROUP BY 1 ) LIMIT 1;
</code></pre>

<p>Schema :  </p>

<pre><code>t1(a,b,c)
t2(b,d,e)
</code></pre>

<p>Error log : </p>

<blockquote>
  <p>Unsupported SubQuery Expression 'b': Correlating expression cannot
  contain unqualified column references.</p>
</blockquote>

<p>What is correlating expression? what are unqualified column references ? and can you generalize the error here ..</p>