How to use "Validator" query in SUI-graphql

Question

I am developing in SUI chain and I want to know how to use "Validator" query. Each time the error message is following.

{
  "data": null,
  "errors": [
    {
      "message": "Unknown field \"Validator\" on type \"Query\".",
      "locations": [
        {
          "line": 2,
          "column": 3
        }
      ]
    }
  ]
}

I want to get specific delegator's rewards from validator in each epoch