Q:

spark scala - Merge mutiple rows into one

I have a dataframe
|--id:string (nullable = true)
|--ddd:struct (nullable = true)
  |-- aaa: string (nullable = true)
  |-- bbb: long(nullable = true)
  |-- ccc: string (nullable = true)
  |-- eee: long(nullable = true)

I am having output like this
 id     |  ddd
--------------------------
   1    | [hi,1,this,2]
   2    | [hello,6,good,3]
   1    | [hru,2,where,7]
   3    | [in,4,you,1]
   2    | [how,4,to,3]

I want the expected o/p as:
   id   |  ddd
  --------------------
   1    | [hi,1,this,2],[hru,2,where,7]
   2    | [hello,6,good,3],[how,4,to,3]
   3    | [in,4,you,1]

Please help

A:

you can collect_list as following 
import org.apache.spark.sql.functions._
df.groupBy("id").agg(collect_list("ddd").as("ddd"))

collect_set works as well
df.groupBy("id").agg(collect_set("ddd").as("ddd"))

