SQL Foundations: Joins & Relationships

Master all JOIN types — INNER, LEFT, RIGHT — and understand how relational tables connect.

~8h total

5 lessons

~3h content

Pro Access

⭐ Certificate of completion

No setup required · 100% browser-based

What You'll Learn

Write INNER JOIN, LEFT JOIN, and RIGHT JOIN queries

Understand one-to-many relationships

Identify and fix duplicate row problems from joins

Join 3+ tables in a single query

Debug join logic confidently

5 lessons · ~150 minutes

INNER JOIN Deep Dive

30 min

Code-Along

LEFT JOIN & Outer Joins

35 min

Code-Along

Table Relationships

25 min

Concept

Joining 3+ Tables

35 min

Code-Along

Debugging Duplicate Rows

25 min

Debugging

PostgreSQLBrowser SQL Editor

Continue Your Journey

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