STRING revenue_str } SALES_DATA ||--o| REVENUE_STRING : converts to 序列图 接下来,我们用序列图来展示数值转字符的过程。 ResultSparkSQLUserResultSparkSQLUserExecute SQL QueryFetch data from sales_dataReturn dataConvert revenue to STRINGDisplay revenue_str 在这个序列图中,用户向 SparkSQL 发出查询...
答案就在org.apache.spark.sql.catalyst.expressions.Cast中, 先看 canCast 方法, 可以看到 DateType 其实是可以转成 NumericType 的, 然后再看下面castToLong的方法, 可以看到case DateType => buildCast[Int](_, d => null)居然直接是个 null, 看提交记录其实这边有过反复, 然后为了和 hive 统一, 所以返...
3.说说Spark SQL的几种使用方式 1.sparksql-shell交互式查询 就是利用Spark提供的shell命令行执行SQL 2.编程 首先要获取Spark SQL编程"入口":SparkSession(当然在早期版本中大家可能更熟悉的是SQLContext,如果是操作hive则为HiveContext)。这里以读取parquet为例: 代码语言:javascript 代码运行次数:0 运行 AI代码解释...
set("spark.sql.shuffle.partitions", "20") val sparkSession = SparkSession.builder().appName("RDD to DataFrame").config(conf).getOrCreate() // 通过代码的方式,设置 Spark log4j 的级别 sparkSession.sparkContext.setLogLevel("WARN") import sparkSession.implicits._ // use case class convert ...
Before concatenation, use theField Settingoperator to convert the timestamp field obtained through theNew Calculation Columnoperator to the long type. REVERSE(String): Returns the string with the order of the characters reversed. For example, to reverse theContract Typestring, you can use the state...
scala> val inserts = convertToStringList(dataGen.generateInserts(10)) inserts: java.util.List[String] = [{"ts": 1688468894617, "uuid": "a7df5838-1139-4560-a024-4a1027dc596d", "rider": "rider-213", "driver": "driver-213", "begin_lat": 0.4726905879569653, "begin_lon": 0.461578584504654...
unhex(expr) - Converts hexadecimalexprto binary. Examples:> SELECT decode(unhex('537061726B2053514C'), 'UTF-8');Spark SQL 20.to_json to_json(expr[, options]) - Returns a json string with a given struct value Examples: >SELECT to_json(named_struct('a', 1,'b', 2)); {"a":1...
package com.matrixone.spark; import org.apache.spark.api.java.function.MapFunction; import org.apache.spark.sql.*; import java.sql.SQLException; import java.util.Properties; /** * @auther MatrixOne * @desc */ public class Mysql2Mo { // parameters private static String master = "local[2]...
但是,有些情况下在将spark.sql.hive.convertMetastoreParquet设为false,可能发生以下异常(spark-2.3.2)。 代码语言:javascript 代码运行次数:0 运行 AI代码解释 java.lang.ClassCastException:org.apache.hadoop.io.LongWritable cannot be cast to org.apache.hadoop.io.IntWritable at org.apache.hadoop.hive.serde...
//SparkSQL程序入口之Spark1.XSQLContext:valsc:SparkContext// An existing SparkContext.valsqlContext=neworg.apache.spark.sql.SQLContext(sc)// this is used to implicitly convert an RDD to a DataFrame.importsqlContext.implicits._HiveContext// sc is an existing SparkContext.valhiveContext=neworg....