User Priveileges Vs. Tables Vs Rows which method is best for accounts/logins

I want to know which is the most efficient way to create accounts and logins.I have trouble deciding which is the better of the three:- User Priveileges- TABLES- Rows

Depends from what you want to do.If you have several groups of people, you can place the first set of people in the same group. then give group privilege to their tables. So, all the people in the same group will be able to share the same info. People from other groups will have no privilege to these tables, for instance they will be able to read info but not to add.Of course, if you are talking about the files permissions, it's different. the owner of the database (you, probably) must have access to all the files, and probably no one other, except the database admin.