BeginnerCoder
DonateLesson 18 — Three-table JOIN
Joining three tables
A many-to-many link — students take many courses, courses have many students — needs a third link table (here enrollments) holding pairs of ids. To get readable names you JOIN all three: students → enrollments → courses. Each JOIN needs its own ON.
FROM readers r
JOIN loans l ON l.reader_id = r.id
JOIN books b ON b.id = l.book_id
Why it matters: tags on posts, products in orders, users in groups — many-to-many is everywhere.
Add the second JOIN to courses so each row shows the course title. Expected: 4 rows of (student, course).
Run your code — when the output matches the task, you will see a green check. Then mark the lesson complete.
Test your knowledgeA quick 3-question quiz on this lesson — instant feedback.
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