Summary - INNER JOIN
- SQL course
- Intermediate
- Lesson 6/115
- 5 min
Write an internal report with self JOIN and chained JOINs.
Summary - INNER JOIN
INNER JOIN combines two tables on a shared column and keeps only matching rows. ON defines the match.
SELECT o.id, c.name
FROM orders o
INNER JOIN customers c ON o.customer_id = c.id;Summary join query.
o.id, c.name is selected from orders o. customers c is joined on o.customer_id = c.id, keeping only matching rows.
Practice Summary - INNER JOIN
Summary: join orders with customers using INNER JOIN.
Starter code
-- summary join
SELECT o.id, c.name
FROM orders o
INNER JOIN customers cSample solution
SELECT o.id, c.name
FROM orders o
INNER JOIN customers c ON o.customer_id = c.id;Expected output
id name 1 Ayşe 2 Mehmet
Questions and answers
Review the lesson questions together with their answers. To test yourself, solve the lesson interactively.
1 What does INNER JOIN keep?
- The matching rows Correct answer
- All rows
- Only the left
- Only the right
Explanation: INNER JOIN keeps only matching rows.
2 Summary - INNER JOIN: match the terms
| Term | Meaning |
|---|---|
INNER JOIN |
intersection |
ON |
match |
WHERE |
filter |
USING |
shortcut |