**SQL**: SELECT SUM(s.amount) AS total_sales FROM sales s JOIN customers c ON s.customer_id = c.id WHERE c.birth_date BETWEEN '1998-01-15' AND '2000-01-15'. **Note**: BETWEEN inclusive. **Spark**: sales.join(customers, 'customer_id').filter((col('birth_date') >= '1998-01-15') &...
Pro-Move: 'We have a birth_date index—this cohort query runs 10x faster; we materialize cohort tables for common segments.' Red Flag: Not knowing BETWEEN is inclusive—off-by-one on boundaries.
This medium-level General/Other question appears frequently in data engineering interviews at companies like Aarete. While less common, it tests deeper understanding that distinguishes strong candidates. Mastering the underlying concepts (join, spark, sql) will help you answer variations of this question confidently.
Break this problem into components. Identify the core trade-offs involved, then walk the interviewer through your reasoning step by step. Demonstrate awareness of edge cases and production considerations - this is what separates good answers from great ones.
SQL: SELECT SUM(s.amount) AS total_sales FROM sales s JOIN customers c ON s.customer_id = c.id WHERE c.birth_date BETWEEN '1998-01-15' AND '2000-01-15'. Note: BETWEEN inclusive. Spark: sales.join(customers, 'customer_id').filter((col('birth_date') >= '1998-01-15') & (col('birth_date') <= '2000-01-15')).agg(F.sum('amount')). Best practice: Index birth_date if frequent; consider timezone.
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Analyze My Answer — FreeAccording to DataEngPrep.tech, this is one of the most frequently asked General/Other interview questions, reported at 1 company. DataEngPrep.tech maintains a curated database of 1,863+ real data engineering interview questions across 7 categories, verified by industry professionals.