[tango12]

@alex_lav: Your SQL query here is exactly what I meant! In SQL, this is easy, both to write and to optimize perf.

Implementing this with GraphQL resolvers (how folks typically write GraphQL servers) is hard - there's a users function and an articles function that are both called, so it's hard to implement those 2 functions contributing together towards a query plan. This was my point.

In fact a REST endpoint that takes a list of users and runs this query with the `IN` part parameterized is easier to build here. But the GraphQL version is a pain.