Fundamentals · Medium · Free
Difference between LEFT, RIGHT, and FULL OUTER JOIN?
FresherFundamentalsDatabase Fundamentals
OUTER JOINs
| Join | Keeps |
|---|---|
| LEFT | All left rows + matches |
| RIGHT | All right rows + matches |
| FULL | Both sides, NULLs where no match |
sql
SELECT c.name, o.id
FROM customers c
LEFT JOIN orders o ON o.customer_id = c.id;LEFT JOIN finds customers with zero orders (o.id IS NULL).