cust    Country Region  value   product
 100    france  europe   1       x
 101    france  europe   2       x
 102    poland  europe   3       x
 103    poland  europe   3       y
 104    france  europe   4       y
 105    france  europe   5       y

cust    Country Region  value   product min_x
 100    france  europe  1   x   1
 101    france  europe  2   x   1
 102    poland  europe  3   x   1
 103    poland  europe  3   y   3
 104    france  europe  4   y   3
 105    france  europe  5   y   3



 df = spark.read.csv('dataset',header=True)
 df1 = df.groupBy('Product').agg(min(df.value).alias('min_x))