Guides
Long-form articles on data interview preparation, reasoning depth, and professional data practice.
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SQL Window Function Interview Questions: The Running Total Trap
A running total is the SQL window question people think they have solved. Here is the default frame decision that quietly breaks it when two rows tie.
2026-07-15 -
A/B Test Interview Questions: What a Good Answer Looks Like
A/B test interview questions test experiment design: metrics, guardrails, power, sample ratio checks, and whether to trust the result.
2026-06-30 -
Bias vs Variance in Data Science Interviews: What It Really Tests
Bias and variance interview questions test whether you can diagnose model failure and choose the right fix, not just define the terms.
2026-06-30 -
Data Analyst Interview Questions: What They Test
Data analyst interview questions test SQL, metric definition, product sense, statistics, and clear communication about what a number means.
2026-06-30 -
Pandas vs SQL: When to Reach for Each
Pandas vs SQL is about choosing the right tool for where the data lives, how large it is, and whether the work is exploratory or shared.
2026-06-30 -
The Data Engineer SQL Interview: What It Tests
Data engineer SQL interviews test grain, joins, idempotency, and scale: the reasoning behind queries that stay correct in production.
2026-06-29 -
Reasoning vs Recall: How to Actually Prepare for Data Interviews
Why memorizing query templates fails under interview pressure, and how training the reasoning behind each answer makes you adaptable.
2026-06-29