dataframe look up and optimization
问题 I am using spark-sql-2.4.3v with java. I have scenario below val data = List( ("20", "score", "school", 14 ,12), ("21", "score", "school", 13 , 13), ("22", "rate", "school", 11 ,14), ("23", "score", "school", 11 ,14), ("24", "rate", "school", 12 ,12), ("25", "score", "school", 11 ,14) ) val df = data.toDF("id", "code", "entity", "value1","value2") df.show //this look up data populated from DB. val ll = List( ("aaaa", 11), ("aaa", 12), ("aa", 13), ("a", 14) ) val codeValudeDf = ll.toDF( "code"