Interview Prep

Interview Prep is built to simulate real interview pressure for analytics engineers, data analysts, and data engineers.

What this section trains:

• writing correct SQL quickly at the right grain
• explaining modeling and metric tradeoffs clearly
• handling ambiguous prompts with explicit assumptions
• debugging wrong answers under time constraints

A candidate is interview-ready when they can:

1. choose the correct grain before writing SQL,
2. deliver a first-correct query quickly,
3. validate with one or more test queries,
4. explain tradeoffs (correctness, readability, performance),
5. recover calmly when assumptions change mid-problem.

Recommended sequence:

1. sql-core: solve core query patterns and avoid join/grain mistakes.
2. timed-mocks: solve under strict 30-minute interview format.
3. follow-up-drills: handle edge cases and interviewer twists.
4. modeling-design and case-studies: explain architecture decisions clearly.

• Round 1 (10 min): clarify assumptions and write a first-correct query.
• Round 2 (10 min): improve correctness/performance and defend your choices.
• Round 3 (10 min): answer follow-up twists, tests, and edge cases.

• Correctness (40%): accurate SQL and metric logic
• Communication (25%): clear assumptions and explanation
• Validation (20%): test query and edge-case coverage
• Performance awareness (15%): sensible optimization reasoning

• writing SQL before declaring grain and definitions
• incorrect joins that duplicate totals
• no validation query before final answer
• weak explanation of tradeoffs or limitations
• no plan for missing/late/dirty data