spark struct 排序测试 的确按照字段先后顺序依次比较

struct排序规则: 按照字段从前到后. 

object Demo1 {
    def main(args: Array[String]): Unit = {
        val spark = SparkSession.builder()
            .master("local[*]")
            .appName(this.getClass.getName)
            .config("spark.ui.port","30101")
            .getOrCreate()
        val sc = spark.sparkContext
        spark.sparkContext.setLogLevel("ERROR")
        // For implicit conversions like converting RDDs to Dataframes
        import org.apache.spark.sql.functions._
        import spark.implicits._

        val ds = Seq(
            C(1, 2)
            , C(8, 20)
            , C(8, 2)
            , C(8, 3)
            , C(4, 1)
            , C(6, 20)
            , C(110, 2)
        ).toDS()
        ds.select(struct('c1,'c2).alias("stt")).orderBy('stt).show()
        spark.stop()
    }
    case class C(c1: Int, c2: Int)
}