create rows from columns in a apache spark dataset

I’m trying from a dataset to create a row from existing columns. Here is my case:

InputDataset

accountid	payingaccountid	billedaccountid	startdate	enddate
0011t00000MY1U3AAL	0011t00000MY1U3XXX	0011t00000ZZ1U3AAL	2020-06-10 00:00:00.000000	NULL

And I would like to have sometthing like this

accountid	startdate	enddate
0011t00000MY1U3AAL	2021-06-10 00:00:00.000000	NULL
0011t00000MY1U3XXX	2021-06-10 00:00:00.000000	NULL
0011t00000ZZ1U3AAL	2021-06-10 00:00:00.000000	NULL

In the input dataset the columns billedaccounid and payingaccounid are now also in accountid column.

Thank you in advance.

Answer

You can create an array column with 3 id columns then use explode function to get desired result.

val spark = SparkSession.builder().master("local[*]").getOrCreate()
spark.sparkContext.setLogLevel("ERROR")
import spark.implicits._

val df = List(("0011t00000MY1U3AAL", "0011t00000MY1U3XXX", "0011t00000ZZ1U3AAL", "2020-06-10 00:00:00.000000", "NULL"))
    .toDF("accountid", "payingaccountid", "billedaccountid", "startdate", "enddate")

df.select(
    explode_outer(array("accountid","payingaccountid","billedaccountid")).as("accountid"),
    'startdate,'enddate).show(false)
/*
+------------------+--------------------------+-------+
|accountid         |startdate                 |enddate|
+------------------+--------------------------+-------+
|0011t00000MY1U3AAL|2020-06-10 00:00:00.000000|NULL   |
|0011t00000MY1U3XXX|2020-06-10 00:00:00.000000|NULL   |
|0011t00000ZZ1U3AAL|2020-06-10 00:00:00.000000|NULL   |
+------------------+--------------------------+-------+ */