No, it doesn't, it is agnostic. There's an adapter for every major database out there. Oh, yeah, graphql also has momentum and strong adoption, unlike SPARQL.
Oh yeah, GraphQL is backed by Facebook (may that be a hint of its momentum, like its support for React?) , unlike SPARQL which is a _standard_. You can also convert from PostgreSQL, MySQL, DB/2 and others to SPARQL. Still, only difference seems 1. Facebook pushing its non-standardized tech around and 2. Losing any benefits from HATEOAS from the usage of GraphQL.
Sure but I use GraphQL as middleware when fetching from elasticsearch, or redis, or flat files. It is not something you hook up directly to your database, it's a way to help define an api for your application.
Most of the time, in my app, resource names do not even correspond to single tables or backend data structures but are simply presented that way for ease of use for external consumers.
Subjectively, Implementing it feels more like old school COBRA than REST or SQL.