Question

I have 3 models, “Coach”, “Team”, and “Event”

An event has attributes away_team and home_team, both of which belong to Team. A team belongs to a coach, and a coach can have many teams.

What I’d like to do is find all events where the home_team is not coached by a particular coach. So, something along the lines of:

Event.where("home_team.team.coach_id NOT ?", coach.id)

The problem is figuring out how to write up that syntax. I’m guessing I need to include the “team” model, but I’m not sure how to write an activerecord include that joins through a specific foreign key.

In short, any ideas on how to do this without getting SQL errors (which I’ve had countless of tonight) would be very appreciated.

Cheers.

Answer 1

If I understand you correctly you need this kind of sql:

SELECT events.* FROM events JOIN team on events.home_team_id = teams.id WHERE teams.coach_id != coach_id

so in rails it should looks something like that:

Event.joins("join teams on events.home_team_id = teams.id").where("teams.coach_id != ?", coach_id)

Of course I don’t know your exact table namings, so you should fit this solution to your problem.

If you have in Event model association: belogns_to: home_team, you can use only joins(:home_team).where(….)