title: why can't I perform a union on dual table SparkSQl?
body: <p>I am trying to generate 2 dummy rows in sparks SQL by using &quot;Dual&quot; table,
  My code is as follows:</p>
  <pre><code>from pyspark.sql.types import *
  from pyspark.sql import Row    
    
  df_dual.registerTempTable(&quot;dual&quot;)
  result = sqlContext.sql(&quot;select 1,[['Red',['ML', 100.0]],['Green'['Litre', 4.0]]] from dual  
                             union 
                           select 2,[['Red1',['M1L', 100.0]],['Green'['Litre', 4.0]]] from dual &quot;)
  
  result.show()
  </code></pre>
  <p>Expected Output :</p>
  <pre><code>1   [[['Red',['ML', 100.0]],['Green'['Litre', 4.0]]]]
  2   [[['Red1',['M1L', 100.0]],['Green'['Litre', 4.0]]]
  </code></pre>
  <p><strong>Error got :</strong>
  An error occurred while calling o207.sql.
  : org.apache.spark.sql.catalyst.parser.ParseException:</p>
  <p>I want to know how to create dummy rows just to experiment few functions using nested data.</p>