oracle - SQL query using SET operator

Question

Using a SET command, show all the countries in region 1 that do not have a location. Display only the country_id.

This is my query and it's wrong. I can't figure it out.

SELECT c.country_id
FROM Countries c
WHERE r.region_id = 1
MINUS
SELECT c2.country_id
FROM Countries c2
WHERE l.location_id IS NULL;

question from:https://stackoverflow.com/questions/65912734/sql-query-using-set-operator

Answer 1

You can use country and location table as follows:

SELECT c.country_id
FROM Countries c
WHERE c.region_id = 1
MINUS
SELECT c2.country_id
FROM location c2;