[Building Sakai] Roles vs Sites table

[Omer A Piperdi]

We are using web services to create the sites from Banner feeds and we 
are seeing a few sites that does not have 'Student' role defined.
Not sure how that happen.

I think roles are in sakai_realm_role table but I would like to run a 
query that give me which sites do not have 'Student' role.. which tables 
involve here???

Thanks
Omer