环境-spark-3.0.1-bin-hadoop2.7、scalalibrarycontainer 2.12.3、scala、sparksql、eclipse-jee-oxygen-2-linux-gtk-x8664
我有一个csv文件，有3列数据类型：string，long，date。我想按第一列（字符串）分组并检索最大日期值。
为此，我从文本文件中创建了person对象的rdd，并将其转换为Dataframe“peopledf”。将Dataframe注册为临时视图。我使用spark提供的sql方法运行以下sql语句。

val maxDateDF = spark.sql("SELECT name, max(birthDate) maxDate FROM people group by name")

但是它没有给出一个名字的正确的最大日期。
我的样本数据如下

Michael, 29,01/03/1992
Justin, 19,01/05/2002
Ben Stokes, 29,01/07/1992
Justin, 18,01/08/2003
Ben Stokes, 29,01/07/1993
Ben Stokes, 29,30/06/1993

如何按其他字段名检索最大日期值组？

package org.apache.spark.examples.sql

import org.apache.spark.sql.Row
import org.apache.spark.sql.SparkSession
import org.apache.spark.sql.types._
import java.sql.Date
import breeze.linalg.max

object SparkSQLExample1 {

case class Person(name: String, age: Long, birthDate: String)

def main(args: Array[String]): Unit = {
val spark = SparkSession.builder().appName("Spark SQL basic example")
.config("spark.master", "local").getOrCreate();
import spark.implicits._
runInferSchemaExample(spark);
spark.stop()
}

 private def runInferSchemaExample(spark: SparkSession): Unit = {
import spark.implicits._
val peopleDF = spark.sparkContext
  .textFile("examples/src/main/resources/people.txt")
  .map(_.split(","))
  .map(attributes => Person(attributes(0), attributes(1).trim.toInt,attributes(2)))
  .toDF()

peopleDF.groupBy("age").count().show();
peopleDF.groupBy("name").avg("age").show();

 peopleDF.createOrReplaceTempView("people")

 implicit val mapEncoder = org.apache.spark.sql.Encoders.kryo[Map[String, Any]]
 val maxDateDF = spark.sql("SELECT name, max(birthDate) maxDate FROM people group by name")
 maxDateDF.map(teenager => teenager.getValuesMap[Any](List("name", "maxDate"))).collect().foreach(println)

}
}