Querying Microsoft SQL Server with Transact-SQL — Lesson 2: Joins, Set Operators, Subqueries, CTEs, and Aggregation

Learning Objectives

• Explain and apply Use inner, outer, cross, and self joins; UNION, INTERSECT, EXCEPT; subqueries; correlated subqueries; and common table expressions.
• Configure, perform, or evaluate Apply GROUP BY, HAVING, aggregate functions, grouping sets awareness, data grain, duplicate control, and result validation.
• Validate the selected approach with documented requirements, evidence, risks, and acceptance criteria.

Detailed Topics

• Core capability: Use inner, outer, cross, and self joins; UNION, INTERSECT, EXCEPT; subqueries; correlated subqueries; and common table expressions
• Implementation workflow: Apply GROUP BY, HAVING, aggregate functions, grouping sets awareness, data grain, duplicate control, and result validation
• Planning: stakeholders, prerequisites, dependencies, scope, assumptions, and expected outcomes
• Security and governance: identity, permissions, data protection, compliance, accessibility, and change control
• Operations: monitoring, logs, validation, documentation, support ownership, and continuous improvement

Guided Demonstration

1. Review the requirement, users, data, dependencies, permissions, risks, and expected result.
2. Demonstrate the relevant configuration, development, analysis, administration, or operational workflow step by step.
3. Capture settings, outputs, logs, screenshots, calculations, test results, and other useful evidence.
4. Compare the observed result with acceptance criteria and explain corrective action where required.

Hands-On Activity

Complete a guided implementation scenario and preserve evidence of settings, outputs, and exceptions.

• Document assumptions, prerequisites, and the planned sequence before starting.
• Test normal, boundary, failure, security, accessibility, and operational conditions.
• Record issues, corrective actions, reusable notes, and the next improvement priority.

Scenario Analysis

• Identify the business or technical decision that must be made.
• Compare valid implementation approaches and their trade-offs.
• Consider security, privacy, accessibility, performance, cost, support, and operational impact.

Troubleshooting Focus

• Separate symptoms from causes and collect evidence before applying a fix.
• Check configuration, data, permissions, dependencies, capacity, connectivity, and recent changes.
• Validate rollback, recovery, ownership, user impact, and business continuity.

Validation Checklist

• The requirement, scope, inputs, and expected outcome are clear.
• The selected design or configuration is documented and follows approved standards.
• Normal, boundary, failure, security, accessibility, and operational conditions are reviewed.
• The result is supported by evidence and the next improvement is prioritized.

Lesson Outcome

Learners can explain and apply Joins, Set Operators, Subqueries, CTEs, and Aggregation in a realistic scenario and validate the result with documented evidence.