Spark SQL quiz

Test your Spark SQL knowledge with a free interactive quiz — 26 questions with answers and explanations. No signup needed to play.

What is a `SparkSession`?

1. What is a `SparkSession`?
2. How do you group and aggregate data?
3. What does `df.printSchema()` show?
4. What is `df.cache()` (or `df.persist()`) used for?
5. What is a Spark DataFrame?
6. How do you join two DataFrames?
7. What is a window function used for in Spark SQL?
8. What is schema inference, and when might you want an explicit schema instead?
9. What is the difference between a "transformation" and an "action" in Spark?
10. What does `df.select("name", "age")` do?
11. What does `df.show()` do?
12. How do you run a raw SQL query against a DataFrame?

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