// 创建视图 data.createOrReplaceTempView("Affairs") val df1 = spark.sql("SELECT * FROM Affairs WHERE age BETWEEN 20 AND 25") df1 ...
val dfList List Hadoop , Java,SQL,Hive,HBase,MySQL , Spark , Scala,SQL,DataSet,MLlib,GraphX dfList: List String, String List Hadoop,Java,SQL,Hive,HBase,MySQL , Spark,Scala,SQL,DataSet,MLlib,GraphX ca ...
2016-11-28 19:05 0 4532 推荐指数:
// 创建视图 data.createOrReplaceTempView("Affairs") val df1 = spark.sql("SELECT * FROM Affairs WHERE age BETWEEN 20 AND 25") df1 ...
data.groupBy("gender").agg(count($"age"),max($"age").as("maxAge"), avg($"age").as("avgAge")).show ...
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 ...
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 ...
Affairs group by gender // 创建视图 data.createO ...
val df6 = spark.sql("select gender,children,max(age),avg(age),count(age) from Affairs group by Cube(gender,children) order by 1,2") df6.show +------+--------+--------+--------+----------+ ...
import org.apache.spark.sql.SparkSession import org.apache.spark.sql.Dataset import org.apache.spark.sql.Row import ...
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 ...