Spark dataframe get column value into a string variable

val maxDate = spark.sql("select max(export_time) as export_time from  tier1_spend.cost_gcp_raw").first()

val rowValue = maxDate.get(0)

The col("name") gives you a column expression. If you want to extract data from column "name" just do the same thing without col("name"):

val names = test.filter(test("id").equalTo("200"))
                .select("name")
                .collectAsList() // returns a List[Row]

Then for a row you could get name in String by:

val name = row.getString(0)