The library is built to query simple dimension/metric based tables. It allows to fetch data in the form you want it.

Query:

query customers{
  fetch(country: US){
    plan {
      revenue: sum(a: planPrice)
    }
  }
}

Response:

{
  free: {
    revenue: 0
  },
  small: {
    revenue: 9000
  },
  large: {
    revenue: 380
  },
  pro: {
    revenue: 500
  }
}

Table Schema: Customer Name, plan, planPrice