PySpark Koans

Learn by fixing tests

Progress0/39

Spark Koans is an independent community tool.

Delta LakeKoan 104

MERGE - Selective Update

Use MERGE with specific column updates. Replace ___ with the correct code.

How it works: Replace the ___ blanks in the code editor with the correct PySpark code, then hit Run Code. Stuck? Try the Hint button.

Setup (read-only)

_reset_delta_tables()

# Create target table with more columns
target_data = [("Alice", 100, "2024-01-01"), ("Bob", 200, "2024-01-01")]
target_df = spark.createDataFrame(target_data, ["name", "balance", "last_updated"])
target_df.write.format("delta").save("/data/accounts")

# Source only has name and new balance
source_data = [("Alice", 500)]
source_df = spark.createDataFrame(source_data, ["name", "new_balance"])

Your CodeCtrl/Cmd+Enter to run

Output

Output will appear here...