How to concat one column records in spark?
<p>I have 2 columns and want to concatenate both, below is the small set of data:</p>

<pre><code>ID         Comments

32412     CLOSE AS NORMAL
32412     UNDER REVIEW 
</code></pre>

<p>I want this to be come as below ,so basically view is that grouping by ID and concatenate the comments.</p>

<pre><code>ID      Comments

32412  CLOSE AS NORMAL
       UNDER REVIEW
</code></pre>