如何在Scala中根据一列或另一列是否与大小写匹配来执行连接？

import org.apache.spark.sql.{SparkSession, functions}
import org.apache.spark.sql.functions._

val spark = SparkSession.builder()
  .appName("Join Example")
  .master("local")
  .getOrCreate()

val df1 = spark.createDataFrame(Seq(
  ("Alice", 25),
  ("Bob", 30),
  ("Charlie", 35)
)).toDF("name", "age")

val df2 = spark.createDataFrame(Seq(
  ("alice", "USA"),
  ("bob", "UK"),
  ("dave", "Canada")
)).toDF("name", "country")

val joinedDF = df1.join(df2, functions.lower(df1("name")) === functions.lower(df2("name")), "inner")

joinedDF.show()