The query I'm running is as follows, however I'm getting this error:
#1054 - Unknown column 'guaranteed_postcode' in 'IN/ALL/ANY subquery'
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 `guaranteed_postcode` NOT IN #this is where the fake col is being used
SELECT `postcode` FROM `postcodes` WHERE `region` IN
My question is: why am I unable to use a fake column in the where clause of the same DB query?