title: SparkSQL second explode after the first explode
body: <p>I am using the following commands to do a second explode after the first explode:</p>
  
  <pre><code>myExplode = sqlContext.sql("select explode(names) as name_x from myTable")
  myExplode = sqlContext.sql("select explode(name_x) as name1 from myTable")
  myExplode.show(6,False)
  </code></pre>
  
  <p>Then I got errors:
   <code>u"cannot resolve 'name_x' given input columns: [names, fieldA, fieldB, fieldC]; line 1 pos 15"</code></p>
  
  <p>However, the first explode works just fine. Is there anything I did wrong in my second explode? </p>
  
  <hr>
  
  <p>Here is an example:</p>
  
  <pre><code>+---------------------------------------------------------------------------------+
  |names                                                                            |
  +---------------------------------------------------------------------------------+
  |[[[Max,White,WrappedArray(SanDiego)],3], [[Spot,Black,WrappedArray(SanDiego)],2]]|
  |[[[Michael,Black,WrappedArray(SanJose)],1]]                                      |
  +---------------------------------------------------------------------------------+
  </code></pre>
  
  <p>After the first explode, I got :</p>
  
  <pre><code>+-----------------------------------------+
  |name_x                                   |
  +-----------------------------------------+
  |[[Max,Black],3]                          |
  |[[Spot,White],2]                         |
  |[[Michael,Yellow],1]                     |
  +-----------------------------------------+
  </code></pre>
  
  <p>I now want to make a second explode on name_x, so I can get [Max,Black], [Spot, White], and [Michael, Yellow]. After this, I even want to do a third explode so I can get only Max, Spot and Michael and put them in a new column. Is this something possible?</p>
  
  <p>Thanks!</p>