You are right. My point, though, was to show how an operator-driven query could be performed, actually neglecting any performance issues. There are some cases, for example, a custom query builder inside an application, where a technique like that could prove handy, especially when dealing with ad hoc reporting inside a database with limited data but needing to have many different views.

I will investigate further and maybe come out with an even better solution. Thank you for your comments!