title: How to convert a column from hex string to long?
body: <p>I have a DataFrame with <code>Icao</code> column with hex codes that I would like to convert to <code>Long</code> datatype. How could I do this in Spark SQL?</p>
  
  <pre><code>|  Icao|count|
  +------+-----+
  |471F8D|81350|
  |471F58|79634|
  |471F56|79112|
  |471F86|78177|
  |471F8B|75300|
  |47340D|75293|
  |471F83|74864|
  |471F57|73815|
  |471F4A|72290|
  |471F5F|72133|
  |40612C|69676|
  </code></pre>