sql - AND multiple JOIN statements in Rails -

i have table users , roles. i'm using has many through relationship. trying create query find users have of roles in array.

ex.

role_ids = [2, 4, 6] user.filter(role_ids) return users have roles ids 2, 4, 6.

this have far.

def self.filter(role_ids)    results = user.joins(:roles).where(roles: {id: role_ids} ) end

the problem statement returns users have @ least 1 of roles in role_ids.

how make statement give me intersection, not union?

i think asking unique instances of users meet role filter criteria. if so, should work.

def self.filter(role_ids)   results = user.joins(:roles).where(roles: {id: role_ids} ).uniq end

KHS