Spark Sql Dataframe Join 一个字段

Question

我对 Spark 很陌生。我有以下查询-->

我有 2 张桌子。业务和检查。 业务表有字段 -> Business_id, name, address 检查表有 --> 分数 我想计算前 10 名的分数。 所以，我需要根据 Business_id 申请加入。我尝试了 2 种方法，但都没有工作 --> 1）使用sqlContext.sql（我写了sql查询）

1)sqlContext.sql("""select CBusinesses.BUSINESS_ID,CBusinesses.name,  CBusinesses.address, CBusinesses.city, CBusinesses.postal_code, CBusinesses.latitude, CBusinesses.longitude, Inspections_notnull.score  from CBusinesses, Inspections_notnull where CBusinesses.BUSINESS_ID=Inspections_notnull.BUSINESS_ID and Inspections_notnull.score <>0 order by Inspections_notnull.score""").show()

2) val df = businessesDF.join(raw_inspectionsDF, businessesDF.col("BUSINESS_ID") == raw_inspectionsDF.col("BUSINESS_ID"))

我应该怎么写？ 谢谢！

Answer 1

val df = businessesDF.join(raw_inspectionsDF, businessesDF("BUSINESS_ID") === raw_inspectionsDF("BUSINESS_ID"))

这应该可行，请查看此处了解更多详细信息：https://spark.apache.org/docs/1.5.1/api/java/org/apache/spark/sql/DataFrame.html

Answer 2

当然...我为每个数据集创建了案例类，然后按选项卡将其拆分，然后将 rdd 转换为数据框

import sqlContext. implicits._
import org.apache.spark.sql.functions._
import org.apache.spark.sql.types._
import scala.util.{Try, Success, Failure}

def parseScore(s: String): Option[Int] = {                                  
  Try(s.toInt) match {
case Success(x) => Some(x)
case Failure(x) => None
}
}

case class CInspections (business_id:Int, score:Option[Int], date:String, type1:String)
val baseDir = "/FileStore/tables/484qrxx21488929011080/"
val raw_inspections = sc.textFile (s"$baseDir/inspections_plus.txt")
val raw_inspectionsmap = raw_inspections.map ( line => line.split ("\t"))   
val raw_inspectionsRDD = raw_inspectionsmap.map ( raw_inspections =>        CInspections (raw_inspections(0).toInt,parseScore(raw_inspections(1)),         raw_inspections(2),raw_inspections(3)))
val raw_inspectionsDF = raw_inspectionsRDD.toDF
raw_inspectionsDF.createOrReplaceTempView ("Inspections")
raw_inspectionsDF.printSchema
//raw_inspectionsDF.show()
val raw_inspectionsDF_replacenull = raw_inspectionsDF.na.fill(0)     //  Replacing null values with '0'
raw_inspectionsDF_replacenull.show()
raw_inspectionsDF_replacenull.createOrReplaceTempView     ("Inspections_notnull")


For Business --> 
  case class CBusinesses (business_id:Int, name: String, address:String,     city:String, postal_code:Int, latitude:String, longitude:String, phone_number:String, tax_code:String, business_certificate:String, application_date:String,owner_name:String, owner_address:String, owner_city:String, owner_state:String,  owner_zip:String )  
val businesses = sc.textFile (s"$baseDir/businesses_plus.txt")
val businessesmap = businesses.map ( line => line.split ("\t"))
val businessesRDD = businessesmap.map ( businesses => CBusinesses (businesses(0).toInt, businesses(1),      businesses(2),businesses(3),businesses(4).toInt,
businesses(5),businesses(6), businesses(7), businesses(8), businesses(9),     businesses(10), businesses(11), businesses(12), businesses(13), businesses(14),     businesses(15)))
 val businessesDF = businessesRDD.toDF
 businessesDF.createOrReplaceTempView ("CBusinesses")
 businessesDF.printSchema
//businessesDF.show()

 It is showing proper resiult for both dataframe
 For Inspection -->
  +-----------+-----+--------+--------------------+
  |business_id|score|    date|               type1|
  +-----------+-----+--------+--------------------+
  |         10|    0|20140807|Reinspection/Foll...|
 |         10|   94|20140729|Routine - Unsched...|
 |         10|    0|20140124|Reinspection/Foll...|
 |         10|   92|20140114|Routine - Unsched...|

For Business -->
+-----------+--------------------+--------------------+-------------+-----------+---------+-----------+------------+--------+--------------------+----------------+--------------------+--------------------+-----------------+-------------+---------+
|business_id|                name|             address|             city|postal_code| latitude|  longitude|phone_number|tax_code|business_certificate|application_date|           owner_name|       owner_address|       owner_city|  owner_state|owner_zip|
+-----------+--------------------+--------------------+-------------+-------    ----+---------+-----------+------------+--------+--------------------+----------    ------+--------------------+--------------------+-----------------+-------------    +---------+
|         10|    Tiramisu Kitchen|       033 Belden Pl|San Francisco|          94104|37.791116|-122.403816|            |     H24|              779059|                    |        Tiramisu LLC|        33 Belden St|    San Francisco|           CA|        94104|
|         17|GEORGE'S COFFEE SHOP|   2200 OAKDALE Ave |         S.F.|          94124|37.741086|-122.401737| 14155531470|     H24|               78443|              4/5/75|"LIEUW, VICTOR & ...| 648 MACARTHUR DRIVE|        DALY CITY|                  CA|    94015|