INNER JOIN returns only rows that have matching values in both tables. The most common type of JOIN.

Basic INNER JOIN

SELECT orders.id, customers.name

FROM orders

INNER JOIN customers ON orders.customer_id = customers.id;

INNER JOIN Multiple Tables

SELECT o.id, c.name, p.product_name

FROM orders o

INNER JOIN customers c ON o.customer_id = c.id

INNER JOIN order_items oi ON o.id = oi.order_id

INNER JOIN products p ON oi.product_id = p.id;

INNER JOIN with Conditions

SELECT o.id, c.name

FROM orders o

INNER JOIN customers c ON o.customer_id = c.id

WHERE o.status = 'completed';

Self JOIN

SELECT e.name as employee, m.name as manager

FROM employees e

INNER JOIN employees m ON e.manager_id = m.id;

INNER JOIN vs WHERE

-- Modern syntax (preferred)

SELECT * FROM orders INNER JOIN customers ON orders.customer_id = customers.id;

-- Old syntax

SELECT * FROM orders, customers WHERE orders.customer_id = customers.id;

Generate INNER JOIN Queries

AI2sql creates optimal JOIN queries.