Lesson 1.1Free
SELECT and joins
Joins combine rows across tables, and the join type decides what happens to the rows with no match. Most wrong result sets are a join type mistake.
5mIntermediate11,890 students
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Overview
Joins combine rows across tables, and the join type decides what happens to the rows with no match. Most wrong result sets are a join type mistake.
What this lesson covers
- Choose between inner, left, right, and full joins
- Join on the right keys and avoid accidental fan-out
- Filter in WHERE versus in the join condition
This lesson sits in SQL Essentials, part of PostgreSQL for Developers. It assumes what came before it and leads directly into the next lesson in the module.
In this lesson you will:
- Choose between inner, left, right, and full joins
- Join on the right keys and avoid accidental fan-out
- Filter in WHERE versus in the join condition