Spark sql default provides a function greatest(Column... exprs) which will "Returns the greatest value of the list of values, skipping null values."
But recently we got a requirement that we needs a function my_greatest(Column... exprs) that
if exprs contains null, then return null
otherwise return the greatest value of the list of values
I checked the UDF of Spark SQL, it seems that I can not defined varargs contains null and can not return null.
Is there any way to implement this? thank you.