I have set up a general user account using phpMyAdmin with no privileges. I can now use GRANT to give SELECT privileges:
GRANT SELECT ON DB.Table TO general@localhost
Is it possible to apply this general user account to users within the table Users and then give them privileges to view only their own data?
For example:
GRANT SELECT ON DB.Booking TO general@localhost IDENTIFIED BY DB.Users.UserId
Database engines do not understand the contents of your tables. You can instruct them to set up a foreign key relationship between the Users table and various other tables in the database, and they can enforce that - but the engine cannot automatically prevent a query from returning data that's tied to a different UserId than the one that's stored in a variable or cookie or whatever, indicating who the person connected to your application is.
That's something that generally must be done specifically by the application. In most cases, I'd expect this to be done by giving the users of the application forms to fill out; from the input on the form, the application would build a query, including whatever business logic applied (like UserId must match the ID value for the user running the query).
If you want to set up every user of your database as an actual database-level login, then some engines (can't recall if MySQL has this capability or not) allow for row-level security. However, this works with users and role set up in the database itself, not user accounts created in and managed by an application.
