Predifined data selection and sorting.

General
1

For example i have 4 tables:

    Users Groups Places Tags
I want to fetch all Users from "Newbie" Group who have been to Places type "Stadium", also i'd love to fetch Tags of this Users. It's not ok to to expose all DB fields and data to the internet via json/js. Is there any way to store some kind of predefined DB queries?
2

You would need to have an additional table to express the “[user] has been to a [place]” relationship. Also, please clarify what you mean by "It’s not ok to to expose all DB fields and data to the internet via json/js. ".

Thanks,
Mark