One of reasons SQL is declarative is that queries run concurrently yet give the illusion of working in isolation. And unlike the concurrency of independent proc

One of reasons SQL is declarative is that queries run concurrently yet give the illusion of working in isolation. And unlike the concurrency of independent processes, which is mostly mechanical, this one involves detailed coordination because database queries work on the same data. With these constraints it may be not that easy to come up with an imperative model that is as simple as the current declarative one.