juniorSQL
What is INNER JOIN?
Updated May 17, 2026
Short answer
INNER JOIN returns matching rows from both tables.
Deep explanation
It combines rows from two tables where the join condition is satisfied.
Real-world example
Linking customers with their orders.
Common mistakes
- Forgetting join conditions causing Cartesian products.
Follow-up questions
- What happens without ON clause?
- How is it different from LEFT JOIN?