Question

Sorry, that’s not a very clear title. Here’s what I’ve got:

SELECT u.name 
FROM users u
    INNER JOIN users_permissions
        ON users_permissions.user_id = u.id
        AND users_permissions.permission_id IN ( 1,2 ) 
    LEFT JOIN users_events
        ON users_events.user_id = u.id
        AND users_events.event_id = 3

Ok, so:

Permission “1” lets you edit all events.
Permission “2” only lets you edit certain events, and those events are specified in table users_events.

I want the query result to include only those users who can edit the specified event.

In pseudo-logic, that’s:

where (permission = 1) or (permission = 2 and event = 3)

The query above will include a user with permission “2” (event-specific) even when the list of events they can edit doesn’t include the event I’m checking against.

In essence, I only care about JOINing the users table to the users_events table if the matched permission in the users_permissions table is “2”.

How do I do that? 🙂

Answer 1

You need to use the WHERE clause:

WHERE perms.permission_id=1 OR (perms.permission_id=2 AND events.event_id=3)