Interview guide

SQL interview: what to prepare

SQL interviews are hands-on almost everywhere — live query writing over sample schemas — with difficulty scaling from joins and aggregation to window functions, and analytical roles adding optimization reasoning.

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Question areas to prepare

  1. 1

    Joins: inner/left/self joins, and reasoning about row multiplication

  2. 2

    Aggregation: GROUP BY with HAVING, conditional aggregation

  3. 3

    Window functions: ROW_NUMBER, RANK, LAG/LEAD, running totals

  4. 4

    Classic prompts: second-highest salary, deduplication, gaps and islands

  5. 5

    Subqueries vs CTEs and when each reads better

  6. 6

    Optimization talk: indexes, EXPLAIN plans, avoiding full scans

The preparation tip that matters most

Master window functions cold — ranking, deduplication, and top-N-per-group questions decide most SQL rounds, and candidates who reach for self-joins where a window function fits signal dated practice.

SQL interview FAQs

What do SQL interviews focus on?

SQL interviews are hands-on almost everywhere — live query writing over sample schemas — with difficulty scaling from joins and aggregation to window functions, and analytical roles adding optimization reasoning.

How should I prepare for a SQL interview?

Master window functions cold — ranking, deduplication, and top-N-per-group questions decide most SQL rounds, and candidates who reach for self-joins where a window function fits signal dated practice.

Does my resume affect the interview itself?

Directly — interviewers build questions from your resume's claims, so every skill and achievement listed becomes fair game. A tailored, honest resume steers the interview toward your strongest material; an inflated one hands the interviewer traps you set for yourself.

The interview starts with your resume

Interviewers build their questions from what your resume claims. Tailor it to the role honestly first — free ATS score, missing keywords, and a recruiter-ready rewrite.