Multi-table JOIN

Join three or more tables in one query.

JOIN and WHERE

After JOIN you can filter the combined result with WHERE.

SELECT o.id, c.name
FROM orders o
JOIN customers c ON o.customer_id = c.id
WHERE c.city = 'İstanbul';

This query returns only orders from customers in Istanbul.

o.id, c.name is selected from orders o. customers c is joined on o.customer_id = c.id, keeping only matching rows. WHERE keeps only the rows where c.city = 'İstanbul' holds.

JOIN and WHERE — details

WHERE comes after JOIN and filters the merged table. The JOIN condition goes in ON; the filter goes in WHERE.

Exercise JOIN and WHERE

JOIN orders and customers; return only orders from Istanbul customers.

Show example solution

SELECT o.id, c.name
FROM orders o
JOIN customers c ON o.customer_id = c.id
WHERE c.city = 'İstanbul'

Test yourself

Filtered join

SELECT o.id, c.name
FROM orders o
JOIN customers c ON o.customer_id = c.id
____ c.city = 'İstanbul';

Show answer

SELECT o.id, c.name
FROM orders o
JOIN customers c ON o.customer_id = c.id
WHERE c.city = 'İstanbul';

Multi-table JOIN: match the terms

JOIN

join
ON

join condition
WHERE

filter
FROM

table
Where does the post-JOIN filter go?
- GROUP BY
- ON
- FROM
- WHERE
Show answer

WHERE — The filter goes in WHERE.

Next lesson: Summary - Simple JOIN

We Are Enhancing Your Experience

Cookie Preferences

Strictly Necessary Cookies

Analytical Cookies