title: How to add the incremental date value with respect to first row value in spark dataframe
body: <p>Input :</p>
  <pre><code>+------+--------+  
  |Test  |01-12-20|  
  |Ravi  |    null|  
  |Son   |    null|
  </code></pre>
  <p>Expected output :</p>
  <pre><code>+------+--------+  
  |Test  |01-12-20|  
  |Ravi  |02-12-20|  
  |Son   |03-12-20|
  </code></pre>
  <p>I tried with <code>.withColumn(col(&quot;dated&quot;),date_add(col(&quot;dated&quot;),1));</code>
  But this result in NULL for all the columns values.</p>
  <p>Could you please help me with getting the incremental values on the date second column?</p>