SQL LEFT JOIN: Examples

Examples
Sample Database

#1

SELECT
	country_id,
	country_name
FROM
	countries
WHERE
	country_id IN ('US', 'UK', 'CN');

#2

SELECT
	country_id,
	street_address,
	city
FROM
	locations
WHERE
	country_id IN ('US', 'UK', 'CN');

#3

SELECT
	c.country_name,
	c.country_id,
	l.country_id,
	l.street_address,
	l.city
FROM
	countries c
LEFT JOIN locations l ON l.country_id = c.country_id
WHERE
	c.country_id IN ('US', 'UK', 'CN')

#4

SELECT
	country_name
FROM
	countries c
LEFT JOIN locations l ON l.country_id = c.country_id
WHERE
	l.location_id IS NULL
ORDER BY
	country_name;

#5

SELECT
	r.region_name,
	c.country_name,
	l.street_address,
	l.city
FROM
	regions r
LEFT JOIN countries c ON c.region_id = r.region_id
LEFT JOIN locations l ON l.country_id = c.country_id
WHERE
	c.country_id IN ('US', 'UK', 'CN');

Table List