PDF guideSQL
SQL for QA — 250 Interview Questions & Answers
250 interview questions and answers on SQL — fundamentals, joins, CTEs, window functions, transactions, performance and database testing — for QA engineers, SDETs, developers and database-focused candidates.
- Questions
- 250 with answers
- Topic areas
- 25
- Level
- Beginner • Intermediate • Senior
- Edition
- First Edition • October 2026
₹299
What's inside
25 topic areas, 10 questions each.
- 01SQL and Database Fundamentals
- 02SELECT Queries and Filtering
- 03Sorting, Grouping, and Aggregation
- 04Joins
- 05Subqueries and Set Operations
- 06Common Table Expressions
- 07Window Functions
- 08CASE, NULL, and Expressions
- 09Data Types and Constraints
- 10INSERT, UPDATE, and DELETE
- 11DDL and Schema Design
- 12Transactions and ACID
- 13Isolation and Concurrency
- 14Indexes and Query Performance
- 15Execution Plans and Optimization
- 16Views, Stored Procedures, and Functions
- 17SQL Security
- 18Database Testing for QA
- 19SQL for API and UI Automation
- 20Date, Time, and Text Operations
- 21Advanced Query Patterns
- 22Pagination and Large Datasets
- 23Data Warehousing and Analytics
- 24SQL Server and Platform Differences
- 25Interview Scenarios, Senior Design, and Best Practices
Sample questions
Excerpts from this guide's answers.
- Q61. What is a window function?
- A window function calculates a value across a set of rows related to the current row (its window) without collapsing those rows into one, unlike GROUP BY.
- Q171. What should be validated in database testing?
- Check that data is stored correctly (values, types, precision), that relationships and constraints hold (keys, uniqueness, required fields), that business rules and calculations are reflected in the stored data, that transactions leave no partial changes, and that migrations, triggers and procedures behave as intended.