Как исправить & ldquo; docker exec & rdquo; требуется как минимум 2 аргумента

Вы можете использовать SUBSTRING (locations. raw, - 6,4), где условие

SELECT `users`.`first_name`, `users`.`last_name`, `users`.`email`,
SUBSTRING(`locations`.`raw`,-6,4) AS `guaranteed_postcode`
FROM `users` LEFT OUTER JOIN `locations`
ON `users`.`id` = `locations`.`user_id`
WHERE SUBSTRING(`locations`.`raw`,-6,4) NOT IN #this is where the fake col is being used
(
SELECT `postcode` FROM `postcodes` WHERE `region` IN
(
 'australia'
)
)