SQL Foundations: Subqueries & CTEs

Write complex multi-step queries using subqueries, CTEs, and UNION — the professional SQL toolkit.

~9h total

5 lessons

~3h content

Pro Access

✦ Includes mini project

⭐ Certificate of completion

No setup required · 100% browser-based

What You'll Learn

Write subqueries in WHERE and FROM clauses

Structure multi-step queries with CTEs

Use UNION and UNION ALL to combine results

Organize complex queries for readability

5 lessons · ~180 minutes

Subqueries in WHERE

30 min

Code-Along

Subqueries in FROM

30 min

Code-Along

CTEs with WITH

40 min

Code-Along

UNION & UNION ALL

25 min

Code-Along

Project: Multi-Step Reporting Query

55 min

Project

PostgreSQLBrowser SQL Editor

Continue Your Journey

Learn the core SQL skills needed to query, summarise, and combine relational data with confidence.