GraphQL is a query language for APIs and a runtime for fulfilling those queries with your existing data.
GraphQL is a syntax that describes how to ask for data, and is generally used to load data from a server to a client. GraphQL has three main characteristics:
- It lets the client specify exactly what data it needs. - It helps you to reduce/optimize API instead of creating all methods by all the use cases.
- It makes it easier to aggregate data from multiple sources.
- It uses a type system to describe data.
Example ) Simple query
Example 2) Query with condition
GraphQL supports various programming languages
C# / .NET
You can see some same codes at https://graphql.org/code/ in various programming languages, and reference query example at https://alligator.io/graphql/introduction-graphql-queries/