SQL For Testers
Tutorials, guides, and interview prep for QA automation engineers.
Scenario-Based SQL Questions for Testers (With Sample Answers)
Real-world SQL scenarios for QA — verifying inserts, UI vs DB validation, user-wise bug counts, foreign key checks, and manual database testing, with answers.
SQL Performance & Optimization: Query Tuning and Indexing
Learn SQL performance tuning — SQL query optimization, how indexing helps, analysing slow queries with EXPLAIN, and database testing tools — for QA and SDET.
Common SQL Queries for Testers (Bug Counts, Test Cases & More)
Practical SQL queries for QA — count bugs in the last 7 days, find users who didn't log in, fetch test cases by module, and count bugs per developer.
Advanced SQL Concepts: Views, Indexes, Normalization, Procedures
Learn advanced SQL Concepts— views vs tables, indexes and performance, normalization (1NF/2NF/3NF), stored procedures, triggers, and functions — with examples.
SQL INSERT, UPDATE, DELETE, Transactions & ACID Explained
Learn SQL data modification — INSERT, UPDATE, DELETE with WHERE, transactions, COMMIT and ROLLBACK, and ACID properties — with clear examples.
SQL Subqueries Explained: Correlated, Nth-Highest Salary & More
Learn SQL subqueries — correlated vs non-correlated, finding the second/nth highest salary, above-average queries, and ORDER BY in subqueries.
SQL Aggregate Functions & Grouping: COUNT, SUM, GROUP BY, HAVING
Learn SQL aggregate functions — COUNT, SUM, AVG, MIN, MAX — plus GROUP BY, HAVING, and WHERE vs HAVING, with clear examples for testers.
SQL Joins Explained: INNER, LEFT, RIGHT, FULL (For Testers)
Learn SQL joins — INNER, LEFT, RIGHT, FULL — plus how to find common records and records in one table but not another, with examples for testers.
SQL SELECT & Filtering: DISTINCT, LIKE, IN, BETWEEN & NULL
Learn to filter data in SQL — SELECT, DISTINCT, LIKE wildcards, IN, BETWEEN, IS NULL vs = NULL, and aliases — with clear examples for testers.
Basic SQL Commands : Keys & Constraints Explained (2026)
Learn basic SQL Commands — what SQL is, DDL/DML/DCL/TCL, DELETE vs TRUNCATE vs DROP, primary/foreign/unique keys, CHAR vs VARCHAR with examples.