在Spark SQL中,可以使用cast函数来实现Long类型到String类型的转换。cast函数用于强制类型转换,可以将Long类型的数据转换为String类型。下面是一个示例代码: ```sql SELECT cast(12345 AS STRING) AS converted_string 1. 2. 上面的代码中,我们将Long类型的数据`12345`通过`cast`函数转换为String类型,并将结果命名...
selectt1.id, t1.id_rand, t2.namefrom(selectid ,casewhenid=nullthenconcat(‘SkewData_’,cast(rand()asstring))elseidendasid_randfromtest1wherestatis_date=‘20221130’) t1leftjointest2 t2ont1.id_rand=t2.id 针对Spark3,可以在EMR控制台Spark3服务的配置页签,修改spark.sql.adaptive.enabled和spar...
"cast(age as string) age", "cast(isGraduated as boolean) isGraduated", "cast(jobStartDate as date) jobStartDate") df3.printSchema df3.show(false) 输出结果如下: root |-- age: string (nullable = true) |-- isGraduated: boolean (nullable = true) |-- jobStartDate: date (nullable =...
day(current_date) as day, hour(current_timestamp) as hour, minute(current_timestamp) as minute, second(current_timestamp) as second; select year(current_date) as year, ( case length(cast( month(current_date) as string) ) when 1 then concat( '0' , cast( month(current_date) as stri...
以下是使用Spark SQL中的cast函数创建具有空值的列的示例代码: 代码语言:scala 复制 import org.apache.spark.sql.functions._ val df = spark.range(5).toDF("num") val dfWithNull = df.withColumn("nullable_num", expr("cast(num as string)")) ...
spark .readStream .format("kafka") .option("kafka.bootstrap.servers", "host1:port1,host2:port2") .option("subscribe", "topic1") .load() .selectExpr("CAST(key AS STRING)", "CAST(value AS STRING)") .writeStream .format("kafka") .option("kafka.bootstrap.servers", "host1:port1,...
SELECT CAST(CAST(id/100 AS INT) AS STRING), name FROM student_delta_external WHERE id BETWEEN 950000000 AND 950500000; 通过如下代码(具体代码请点击“阅读原文”),读取test表对应的文件夹内的数据并转换为JavaPairRDD存于leftRDD中,同样读取test表对应的数据存于rightRDD中。通过RDD的join算子对leftRDD与ri...
val dataSizeQuery = s"SELECT SUM(LENGTH(CAST(data AS STRING))) FROM your_table_name" val dataSize = spark.sql(dataSizeQuery).collect()(0)(0).asInstanceOf[Long] println(s"Data size: $dataSize bytes") 方法三:使用Spark的count()和limit()方法 代码语言:txt 复制 val sampleSize = 100...
ds1.selectExpr("topic", "CAST(key as STRING)", "CAST(value AS STRING)") .writeStream.format("kafka") .option("checkpointLocation", "/kafka/checkpoint/dir") .option("kafka.bootstrap.servers", "b-1.tang-kafka-plain.hnjunx.c4.kafka.cn-north-1.amazonaws.com.cn:9092,b-2.tang-kafka-...
ETL:只获取通话状态为success日志数据 /* val etlStreamDF: Dataset[String] = kafkaStreamDF .selectExpr("CAST(value AS STRING)") // 提取value字段值,并且转换为String类型 .as[String] // 转换为Dataset[String] .filter{msg => null != msg && msg.trim.split(",").length == 6 && "success"....