MODULE 3 · Working across tables
Reading · 15 min
Inner joins
Inner joins
Joins let a query follow relationships between tables. Start by identifying each table's key and the exact relationship you expect.
Learning objectives
- Write an INNER JOIN
- Identify the matching keys
Combine rows that have a matching related record. Focus on explaining each decision in your own words before relying on a pattern or shortcut.
Example
SELECT orders.id, customers.name
FROM orders
INNER JOIN customers ON customers.id = orders.customer_id;Summary
KEY TAKEAWAYS
- A join follows a defined relationship.
- Check row counts after a join.
Reading material
Inner joins practice prompt
Use the exercise in this lesson to check your understanding.
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