SQL joins question

I want to link up 3 tables to list all members of a particular group. My code (which is wrong) looks like this:

@group_members = Membership.find( :all, :joins => ['FROM memberships INNER JOIN groups ON memberships.group_id= group.id' + 'INNER JOIN users ON memberships.user_id=users.id'])

this form of sql assumes that you are giving it a list of associaton names, ie

Membership.find(:all, :joins => [:groups, :users]) looks like it would do what you are trying to do.

The other form involves sql fragments, in which case you must provide one such fragment, not an array ie

@group_members = Membership.find( :all,                                    :joins => 'INNER JOIN groups ON memberships.group_id= group.id INNER JOIN users ON memberships.user_id=users.id')