Spark SQL - Generate array of arrays from the sql function
<p>I want to create an array of arrays. This is my data table:</p>

<pre><code>// A case class for our sample table
case class Testing(name: String, age: Int, salary: Int)

// Create an RDD with some data
val x = sc.parallelize(Array(
    Testing(null, 21, 905),
    Testing("Noelia", 26, 1130),
    Testing("Pilar", 52,  1890),
    Testing("Roberto", 31, 1450)
 ))

// Convert RDD to a DataFrame 
val df = sqlContext.createDataFrame(x) 

// For SQL usage we need to register the table
df.registerTempTable("df")
</code></pre>

<p>I want to create an array of integer column "age". For that I use "collect_list":</p>

<pre><code>sqlContext.sql("SELECT collect_list(age) as age from df").show
</code></pre>

<p>But now I want to generate an array containing multiple arrays as created above:</p>

<pre><code> sqlContext.sql("SELECT collect_list(collect_list(age), collect_list(salary)) as arrayInt from df").show
</code></pre>

<p>But this does not work , or use the function org.apache.spark.sql.functions.array. Any ideas?</p>