val query4 = octDF
      .join(novDF, octDF("user_id") === novDF("user_id"))
      .filter(octDF("event_type") === "view" )
      .groupBy(octDF("category_id"))
      .agg(avg(novDF("price")).as("avgPrice"))
      .orderBy(desc("avgPrice"))

query4.explain()
spark.time(query4.show(false))