How to use built in spark UDF's

In the i talked about how to create a custom UDF in scala for spark. But before you do that always check Spark UDF's that are available with Spark already. I have this sample Spark data frame with list of users

	case class User(firstName:String, lastName: String, age:Integer)
	val users = Seq(
	User("Sachin","Tendulkar",43),
	User("Rahul","Dravid",43),
	User("Virat","Kohli",27),
	User("MahendraSingh","Dhoni",34)
	)
	val userDF = sc.parallelize(users).toDF()

view raw createdf.scala hosted with ❤ by GitHub

I wanted to sort the list of users in descending order of age so i used following 2 lines, first is to import functions that are available with Spark already and then i used desc function to order age in descending order

import org.apache.spark.sql.functions._
display(userDF.orderBy(desc("age")))

Now if i wanted to sort the data frame records using age in ascending order

display(userDF.orderBy(asc("age")))

This is sample of how to use the sum() function

userDF.select(sum("age")).show