title: run a bulk update query in cassandra on 1 column
body: <p>we have a scenario where a table in cassandra which has over million records and we want execute a bulk update on a column(basically set the column value to null in entire table).</p>
  
  <p>is there a way to do so since below query won't work in CQL</p>
  
  <pre><code>UPDATE TABLE_NAME SET COL1=NULL WHERE PRIMARY_KEY IN(SELECT PRIMARY_KEY FROM TABLE_NAME );
  </code></pre>
  
  <p>P.S - the column is not a primary key or a cluster key.</p>