Earlier quoted context omitted.
But the users are going to issue those N queries while you're still at the whiteboard talking about big-O notation. Exposing a full query language to the database system means that you have the opportunity to optimize the query fully. Limiting the query language only limits your ability to optimize, so you won't even be able to explain to the user that there's an alternative way to get their answer without bringing d…
Limiting the query language only limits your ability to optimize This seems backwards. The more general a language is, the harder it is to analyze and transform, and that is what optimizers do.
It might be hard to optimize a more general language, but it's impossible to optimize something that can't be expressed in a simple language.