GP misunderstood what an "ambiguous join" is. Rather than a join that returns multiple results, they're more like when you have relationships like this [0]:

GP misunderstood what an "ambiguous join" is. Rather than a join that returns multiple results, they're more like when you have relationships like this [0]: user.residence1 -> country user.residence2 -> country user.join(country) You have to specify somewhere which foreign key to follow, it can't be figured out automatically. GP's suggestion doesn't work because there's no way to automatically determine which one to use. I'm only really familiar with Django, and it handles this type of thing by making you specify the "residence1" name instead of the table name "country". [0] To refer back to the top of this comment chain, that user is complaining they can't do something like also have a "country->continent" relationship and do "user.join(continent)" and have the system figure out the two joins needed.