parameter in Kotlin Primary constructor

var/val within constructor declares a property inside the class. When you do not write it, it is simply a parameter passed to the primary constructor, where you can access the parameters within the **init** block or use it initilize other properties.  Constructor parameter is never used as a property.

SAP HANA: get max record for a group

1. With Rank node

2. With Aggregation/Join node

Performance:

Rank node wins.