Item_sale_table
    item_id   date   Sale Amount
    aaa       3-11      20
    aaa       3-12      21
    aaa       3-13      28
    ...       ...       ...
    bbb       3-11      17
    bbb       3-12      12
    ...       ...       ...
    ccc       3-11      9
    ...       ...       ...

item_id   description
aaa          xxxx
bbb          xxxyx
ccc          zxsa
...

def ItemProcess (item_id: String, Dataset: DataFrame)  = {

      val item_count = Dataset.filter(Dataset("item_id").contains(item_id)).count()

      println(item_id,item_count)

  }

val item_count_collection = item_list.select("item_id").foreach(x => ItemProcess(x(0).toString, item_sale_table))

ERROR Executor: Exception in task 4.0 in stage 11.0 (TID 504)
java.lang.NullPointerException
    at org.apache.spark.sql.DataFrame.resolve(DataFrame.scala:151)
    at org.apache.spark.sql.DataFrame.col(DataFrame.scala:664)
    at org.apache.spark.sql.DataFrame.apply(DataFrame.scala:652)