Atlas › 15 SQL & Database Testing › JOINs and Aggregation☰ Read as one page
JOINs and Aggregation
2.1OverviewWhen you find a bug, SQL helps you investigate scope, patterns, and root cause. JOINs combine data across tables. GROUP BY and HAVING…2.2JOIN Types2.3Common JOIN Patterns for QA2.4GROUP BY and HAVINGGROUP BY collapses rows into groups. HAVING filters groups (like WHERE, but for aggregated data).2.5Subqueries2.6Using JOINs in Test Automation2.7Practical Exercise1. Write a query that finds users who registered but never placed an order 2. Write a query that finds duplicate email addresses in the…2.8Key Takeaways- LEFT JOIN finds orphaned records and missing relationships - GROUP BY + HAVING reveals duplicates, patterns, and distributions…