MySQL Joins Explained with Examples

What are JOINs?

JOINs combine rows from two or more tables based on a related column. They're how relational databases connect data.

Sample Tables

users:  id | name        orders: id | user_id | total
        1  | Sara                1  | 1       | 100
        2  | Ali                 2  | 1       | 50

INNER JOIN — Matching Rows Only

SELECT users.name, orders.total
FROM users
INNER JOIN orders ON users.id = orders.user_id;
-- Sara 100, Sara 50 (Ali has no orders, excluded)

LEFT JOIN — All Left + Matches

SELECT users.name, orders.total
FROM users
LEFT JOIN orders ON users.id = orders.user_id;
-- Sara 100, Sara 50, Ali NULL

Types of JOINs

JOIN	Returns
INNER	Only matching rows
LEFT	All left + matches
RIGHT	All right + matches
FULL (via UNION)	All rows both sides

FAQs

INNER vs LEFT JOIN?

INNER drops non-matching rows; LEFT keeps all left-table rows. More in our MySQL section.

Can I join more than two tables?

Yes — chain multiple JOINs.