title: How to remove a variable from hiveconf
body: <p>I set a variable in <code>hive</code> using the set command:</p>
  
  <pre><code>set a = value;
  </code></pre>
  
  <p>and I can use <code>${hiveconf:a}</code> to retrieve the value of a, namely <code>value</code>.
  However, I couldn't find the way to delete this variable <code>a</code> from the hiveconf.
  I tried </p>
  
  <pre><code>set a = ;
  </code></pre>
  
  <p>but when I use <code>set -v</code> to look at all the defined hiveconf properties and variables, it gives <code>a=</code>, the variable a is still there although it does not have a value. </p>
  
  <p>Is there a way to remove this variable <code>a</code> from hiveconf?</p>