How to get non-null sorted ascending data from Spark DataFrame?

Question

I load the data into data frames where one of the columns is zipCode (String type). I wonder how to get non-null values for that column in ascending order in Scala? Many thanks in advance.

Answer 1

scala> val df = Seq("2", "1", null).toDF("x")
df: org.apache.spark.sql.DataFrame = [x: string]

scala> df.orderBy($"x".asc_nulls_last).show
+----+
|   x|
+----+
|   1|
|   2|
|null|
+----+