Just a tiny teaser, you could write something like

    Person { country => name }

And it will output the following SQL:

    -- target: postgres
    SELECT country, array_agg(name) AS name FROM Person GROUP BY country

Sort of, GraphQL is just an interface that describes your data models, but you need to implement "resolvers" for each operation that tells the server how to fetch/mutate the queried data.

So you might have a GQL type like:

    type User {
      name: String
      age: Int
    }

But you need to implement a query with business logic for fetching this data, and that can be anything (but generally, a DB call).

Projects like Hasura kind of blur this line, as it's essentially one big GQL -> SQL JIT compiler in Haskell though.