join in a dataframe spark java

Question

First of all, thank you for the time in reading my question.

My question is the following: In Spark with Java, i load in two dataframe the data of two csv files.

Answer 1

You can use join method with column name to join two dataframes, e.g.:

Dataset  dfairport = Load.Csv (sqlContext, data_airport);
Dataset  dfairport_city_state = Load.Csv (sqlContext,   data_airport_city_state);

Dataset  joined = dfairport.join(dfairport_city_state, dfairport_city_state("City"));

There is also an overloaded version that allows you to specify the join type as third argument, e.g.:

Dataset joined = dfairport.join(dfairport_city_state, dfairport_city_state("City"), "left_outer");

Here's more on joins.