#MySQL #course #tutorial

00:00:00 intro
00:01:46 INNER JOIN
00:03:48 LEFT JOIN
00:04:20 RIGHT JOIN
00:04:45 conclusion

INNER JOIN selects records that have a matching key in both tables.
SELECT *
FROM transactions INNER JOIN customers
ON transactions.customer_id = customers.customer_id;

LEFT JOIN returns all records from the left table
and the matching records from the right table
SELECT *
FROM transactions LEFT JOIN customers
ON transactions.customer_id = customers.customer_id;

RIGHT JOIN returns all records from the right table
and the matching records from the left table
SELECT *
FROM transactions RIGHT JOIN customers
ON transactions.customer_id = customers.customer_id;