Which join operation in Apache Spark enables us to combine two DataFrames based on a common column or key?

Which join operation in Apache Spark allows you to combine two DataFrames based on a common key?

Which join operation in Apache Spark returns all the rows from both DataFrames, filling in null values for non-matching rows?

Which join operation in Apache Spark returns all the rows from the left DataFrame and the matching rows from the right DataFrame?

Which join operation in Apache Spark includes all the rows from the right DataFrame and the matching rows from the left DataFrame?

Which join operation in Apache Spark can be used to combine two DataFrames based on multiple common keys?

Which join operation in Apache Spark can be used to combine two DataFrames without specifying a common key?

Which join operation in Apache Spark combines two DataFrames based on a common key and returns all the rows from both DataFrames?

Which join operation in Apache Spark combines two DataFrames and returns only the rows that have matching keys in both DataFrames?

What is the result of an 'inner' join between two dataframes in Apache Spark?