I like to think of GraphQL as an ORM that hides the complexity of SQL queries. It is a DSL from the logic family. That it happens to be used in web services is secondary to understanding how it works. Could be used in a different context entirely.
I'm having trouble seeing what features GraphQL gets from the logic family. The query feels more like a way to execute a series of function calls with parameters, like a chain of promises. You can't really encode any logic or do even simple filters like "WHERE foo < bar", beyond what arguments have been added to each field.