1. SQL Basics
Tables, rows, columns, SELECT, WHERE, ORDER BY, LIMIT, and clean query habits.
Open lessonDatabase Skills
SQL for real projects, testing, and interviews.
A practical path from basic queries to joins, aggregations, constraints, indexes, transactions, and QA database validation. Built for people who need to test, debug, and explain data confidently.
Learning Path
Follow these lessons in order. Each page is compact, example-first, and focused on what you will use in QA automation, API testing, backend debugging, and interviews.
2. Joins and Relationships
Primary keys, foreign keys, INNER JOIN, LEFT JOIN, and common join mistakes.
Open lesson3. Aggregation and Reports
COUNT, SUM, AVG, GROUP BY, HAVING, and building test/report queries.
Open lesson4. Data Design
Normalization, constraints, NULL handling, indexes, and schema quality checks.
Open lesson5. Transactions
ACID, commits, rollbacks, isolation, and how testers validate data consistency.
Open lesson6. Practice Set
Hands-on tasks based on ecommerce, HRM, API responses, and defect triage.
Open practiceWhat Makes This Modern
PostgreSQL-friendly syntax
QA validation examples
API + database checks
Interview patterns
Production debugging mindset