Apache Spark Spark SQL and DataFrames

Question 1

What is the entry point for Spark SQL functionality in Spark 2.x and later?

Accepted Answer

SparkSession

Answer

SparkContext

Answer

SQLContext

Answer

HiveContext

Question 2

Which method is used to run a SQL query on a registered temporary view in Spark SQL?

Accepted Answer

spark.sql()

Answer

spark.execute()

Answer

spark.query()

Answer

spark.runSQL()

Question 3

What is a DataFrame in Apache Spark?

Accepted Answer

An RDD of Row objects with a named column schema

Answer

A distributed key-value store

Answer

An immutable list of serialized Java objects

Answer

A streaming data source

Question 4

How do you register a DataFrame as a temporary SQL view in Spark?

Accepted Answer

df.createOrReplaceTempView("name")

Answer

df.registerTable("name")

Answer

df.toTable("name")

Answer

spark.registerView(df, "name")

Question 5

Which DataFrame function is used to select specific columns?

Accepted Answer

select()

Answer

filter()

Answer

where()

Answer

pick()

Question 6

What does the printSchema() method do in Spark DataFrames?

Accepted Answer

Prints the schema of the DataFrame in a tree format

Answer

Prints all rows of the DataFrame

Answer

Displays the first 20 rows

Answer

Exports the schema to a file