尽管我在GraphiQL上成功测试了graphQL查询之后，从GraphiQL工具中复制并粘贴了它，但当我在一个reactJS应用程序中的Apollo客户端中尝试该查询时，该查询返回了一个错误：

[GraphQL error]: Message: Cannot query field "allStudents" on type "Query"., Location: [object Object], Path: undefined

下面是我的实现：

const link = createHttpLink({
  uri: 'http://localhost:8000/graphql',
  fetchOptions: { method: "POST" }
});

const client = new ApolloClient({
  link: link 
});

const GET_STUDENTS = gql`
query getStudents($schoolID: Int!){
  allStudents(schoolId: $schoolID){
    pickUpLat
    pickUpLng
  }
}
`;

client
  .query({
    query: GET_STUDENTS,
    variables: { schoolID: 1 }
  })
  .then(result => console.log(result));

可能有什么问题？下面是我所期望的正确答案：

{
  "data": {
    "allStudents": [
      {
        "pickUpLat": 31.9752942479727,
        "pickUpLng": 35.8438429235775
      },
      {
        "pickUpLat": 31.9754545979993,
        "pickUpLng": 35.8437478537235
      }
    ]
  }
}

EDIT我使用GraphiQL得到预期的结果：

编辑2

我尝试比较我的请求和GraphiQL请求之间的有效负载：
我的请求的负载：（它有__typename，我不知道为什么）

{"operationName":"getStudents","variables":{"schoolID":1},"query":"query getStudents($schoolID: Int) {\n  allStudents(schoolId: $schoolID) {\n    pickUpLat\n    pickUpLng\n    __typename\n  }\n}\n"}

GraphiQL请求的负载：

{"query":"query getStudents($schoolID: Int!){\n  allStudents(schoolId: $schoolID){\n    pickUpLat\n    pickUpLng\n  }\n}","variables":{"schoolID":1},"operationName":"getStudents"}

他们几乎一模一样，知道吗？