3 pages from the guide: the cover, the contents (50 questions in 6 sections) and one complete question with its answer, code and interview tips.
SQL questions appear in backend, data and even front-end interviews, and the same query problems come up again and again. This guide covers joins and NULL rules, the classic query problems such as Nth highest salary, top-N per group and gaps and islands, window functions and frames, subqueries, recursive CTEs and UPSERT, indexes, EXPLAIN and keyset pagination, schema design, and calling SQL from Java.
50 questions in 6 sections, 50 code examples and 4 diagrams in a 44-page PDF (2026 edition).
Handwritten SQL and DBMS notes, cheat sheets and 200+ real interview questions, from basics to advanced.
No reviews yet
Write every query yourself against a local PostgreSQL before reading the answer. Then explain one EXPLAIN plan out loud, step by step.
Three standard answers: MAX below the MAX (second highest only); DISTINCT + ORDER BY + OFFSET n-1 LIMIT 1; and `DENSE_RANK()`, which generalises to any N and handles ties correctly. All must work on distinct salary values, or two people sharing the top salary make the "second highest" equal to the highest.
It is a digital download (PDF). After payment it appears in your Library right away.
It covers this topic in depth. It is one topic from the TechTribers Java Interview Series, which has all 23 parts (1,200+ questions) in one bundle.
No reviews yet — be the first to review this product.
A self-paced data engineering program from foundations to job-ready skills: SQL, Python, ETL, Airflow and projects.
No reviews yet
150+ frequently asked microservices interview questions with explanations, hands-on examples and mock interviews.
No reviews yet
Tech Tribers