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Practice

Drill the part you are weakest on.

The Daily Brick gives everyone the same five questions. Practice lets you choose: one topic at one difficulty, or the mixed set for your role. Same question bank, same rule: every code question ran on Spark before it shipped.

By topic

Ten questions at the difficulty you pick.

  • Core: semantics you should have
  • Edge cases: the ones you have not hit yet
  • Subtle: the ones that only show up in production
Delta Lake

Versions, time travel, MERGE, and what a commit actually rewrites.

Spark

DataFrame semantics, nulls, joins, and lazy evaluation.

SQL

Window functions, aggregation, and the null rules that decide a result.

Pipelines

The transformations where correct and merely quiet diverge.

Data quality

Constraints, dedup, and the silent row loss nobody notices.

You can practise without an account. Sign in to keep your best score per set and turn what you get wrong into a reading list on your account page.