Get inactive customers using left outer join between orders and customers.

InactiveCustomers.scala

/*
sqoop import \
  --connect jdbc:mysql://ms.itversity.com:3306/retail_db \
  --username retail_user \
  --password itversity \
  --table orders \
  --target-dir data/retail_db/orders \
  --as-textfile \
  --num-mappers 1
  */

  /*
sqoop import \
  --connect jdbc:mysql://ms.itversity.com:3306/retail_db \
  --username retail_user \
  --password itversity \
  --table customers \
  --target-dir data/retail_db/customers \
  --as-textfile \
  --num-mappers 1
  */

  /* Data is available in local file system /data/retail_db
Source directories: /data/retail_db/orders and /data/retail_db/customers
Source delimiter: comma (“,”)
Source Columns - orders - order_id, order_date, order_customer_id, order_status
Source Columns - customers - customer_id, customer_fname, customer_lname and many more
Get the customers who have not placed any orders, sorted by customer_lname and then customer_fname
Target Columns: customer_lname, customer_fname
Number of files - 1
Target Directory: /user/<YOUR_USER_ID>/solutions/solutions02/inactive_customers
Target File Format: TEXT
Target Delimiter: comma (“, ”)
Compression: N/A  */

/*
spark-shell --master yarn \
  --conf spark.ui.port=12345 \
  --num-executors 1 \
  --executor-cores 1 \
  --executor-memory 2G
*/

  val orders = sc.textFile("data/retail_db/orders")
  val customers = sc.textFile("data/retail_db/customers")
  val ordersRDD = orders.map(rec => (rec.split(",")(0), rec.split(",")(2)))
  val customersRDD = customers.map(rec => {
      val r = rec.split(",")
      (r(0),r(1),r(2))
  })
  val ordersDF = ordersRDD.toDF("order_id","order_customer_id")
  val customersDF = customersRDD.toDF("customer_id","customer_fname","customer_lname") 

  //sqlContext
  ordersDF.registerTempTable("orders")
  customersDF.registerTempTable("customers")

  val sqlResult = sqlContext.sql("select customer_lname, customer_fname "+
            "from customers c left outer join orders o on "+
            "o.order_customer_id = c.customer_id "+
            "where o.order_customer_id is null "+
            "order by c.customer_lname, c.customer_fname")

sqlResult.coalesce(1).map(rec => rec.mkString(",")).saveAsTextFile("user/gontiv/solutions/solutions02/inactive_customers") 

//CoreApi
  val ordersRDD = orders.map(rec => (rec.split(",")(2), rec.split(",")(0)))
  val customersRDD = customers.map(rec => {
      val r = rec.split(",")
      (r(0),(r(2),r(1)))
  })

val leftJoinData = customersRDD.leftOuterJoin(ordersRDD);
val temp = leftJoinData.filter(rec => rec._2._2 == None).map(rec => rec._2).sortByKey()
temp.map(rec => rec._1._1+" , "+rec._1._2).coalesce(1).
saveAsTextFile("user/gontiv/solutions/solutions02_core/inactive_customers")