Spark2 Dataset之视图与SQL
// 创建视图 data.createOrReplaceTempView("Affairs") val df1 = spark.sql("SELECT * FROM Affairs WHERE age BETWEEN 20 AND 25") df1 ...
原文：Spark2 Dataset多维度统计cube与rollup
val df spark.sql select gender,children,max age ,avg age ,count age from Affairs group by Cube gender,children order by , df .show gender children max age avg age count age null null . . null no . . ...
2016-11-25 18:23 1 2709 推荐指数：
相关推荐
Spark2 Dataset聚合操作
data.groupBy("gender").agg(count($"age"),max($"age").as("maxAge"), avg($"age").as("avgAge")).show ...
Spark2 DataSet 创建新行之flatMap
val dfList = List(("Hadoop", "Java,SQL,Hive,HBase,MySQL"), ("Spark", "Scala,SQL,DataSet,MLlib,GraphX")) dfList: List[(String, String)] = List ...
Spark2 Dataset去重、差集、交集
import org.apache.spark.sql.functions._ // 对整个DataFrame的数据去重 data.distinct() data.dropDuplicates() // 对指定列的去重 val colArray=Array ...
Spark2 Dataset持久化存储级别StorageLevel
import org.apache.spark.storage.StorageLevel // 数据持久缓存到内存中//data.cache()data.persist() // 设置缓存级别data.persist(StorageLevel.DISK_ONLY) // 清除缓存 ...
Spark2 Dataset之collect_set与collect_list
collect_set去除重复元素；collect_list不去除重复元素select gender, concat_ws(',', collect_set(children)), ...
Spark2 Dataset DataFrame空值null,NaN判断和处理
import org.apache.spark.sql.SparkSession import org.apache.spark.sql.Dataset import org.apache.spark.sql.Row import ...
Spark2 Dataset行列操作和执行计划
Dataset是一个强类型的特定领域的对象，这种对象可以函数式或者关系操作并行地转换。每个Dataset也有一个被称为一个DataFrame的类型化视图，这种DataFrame是Row类型的Dataset，即Dataset[Row] Dataset是“懒惰”的，只在执行行动操作时触发计算 ...