OData - which was essentially LINQ over URL - was nice (but incomplete) idea with terrible realization. We've used it in two projects in the past and we've fallen back from using it in both cases:

- OData never got wider adoption outside (and even inside) MS. GraphQL is already adopted on every major platform.

- OData had shitton of documentation and format changes with every version. Backward compatibility not included. GraphQL has clear specification which is pretty stable since its first publication.

- OData queries had no validation. You could send almost every query just to get runtime response that your framework/library doesn't support that functionality - even if it was developed by Microsoft itself. On the contrary all major GraphQL server implementations have full feature support.

- Thanks to Introspection API GraphQL has self-descriptive metadata model, which is great for tooling and compile time query verification. Also versioning, schema and documentation are all included into GraphQL from start.

- And finally GraphQL focuses on exposing capabilities of your service into well defined format understood by frontend, not on exposing subset of your database to the user - like OData did.