How to get increasing and decreasing sale in dataframe find via pyspark 

df = spark.read.format("csv").option("header","True").load("file:////home/cloudera/medi.txt")     

df.show()

windowspec = Window.partitionBy("ProductID").orderBy("year")

resultdf = df.withColumn("sales",lag("Sold",1).over(windowspec))

resultdf.show()

dff = resultdf.withColumn("comp",col("Sold")-col("sales"))

dff.show()

res = dff.filter(col("comp")>=0).select("ProductID","ProductName").distinct()

res.show()

res2 = dff.filter(col("comp")<0).select("ProductID","ProductName").distinct()

res2.show()