Question

This is my current query – its not getting the required result. I want it do display all of the “resources” even if they dont have a connection.

SELECT *
FROM (`user_permissions`)
JOIN `user_groups` ON `user_groups`.`id` = `user_permissions`.`role`
JOIN `user_resources` ON `user_resources`.`id` = `user_permissions`.`resource`
WHERE `role` = '4'

When I try left join or right join it still returns the same result. The result I get is:

id   | role  | resource | name

5    | 4     |        2 | Changelog 

I want

id   | role  | resource | name

5    | 4    |   2 | Changelog 
null | null | null | Resource2 
null | null | null | Resource3

Is this possible?

Answer 1

Looking through your query, role is part of user_permissions which is one of the connections that may or may not exist. Consider changing your where clause to WHERE `role`= '4' OR `role` IS NULL if you want to display these null records as well…

Also, although this can be accomplished by a right join, I believe it’s more readable/understandable if you select from user_resources instead, then left join on the other tables. This follows from your problem description statement; you want to “display all of the ‘resources’ even if they don’t have a connection”, which means you want to select from resources, then join on any connections if they exist.