apache spark agg( ) function

Question

For a sample dataframe scholor,

scala> scholor.show

| id|  name|age|sal|base|

For above, both below, gives same output. What will be use of agg() then. It just for name.

scala> scholor.groupBy("age").sum("base").show      /*with out agg */

scala> scholor.groupBy("age").agg(sum("base")).show        /* with agg */

+---+---------+
|age|sum(base)|
+---+---------+

Does agg() need any varargs as arguments? What is need of agg()?

Thanks in advance.

Answer 1

In order write .sum this method has to exist. It is hardcoded on the API. Using .agg you can provide other aggregating functions, sum("column") is just one of them.