title: Graphql - How to perform where clause
body: <p>I am new to graphql and I am struggling with a query.
  I want to return a user by their email address</p>
  
  <p>I have a type defined call V1User and it has the following fields
  id,
  email,
  password,
  role</p>
  
  <p>What needs to change in this query to return a user based on email?</p>
  
  <pre><code>    query GetAllV1User {
    viewer {
       allV1Users{
        edges {
          node {
            id
            email
            role
            createdAt
            modifiedAt
          }
        }
      }
    }
  }
  </code></pre>
  
  <p>I tried this query</p>
  
  <pre><code>    query getV1UserQuery($email: String!) {
    getV1User(email: $email) {
      id
      email
    }
  }
  </code></pre>
  
  <p>With these params</p>
  
  <pre><code>{"email": "test@test.com"}
  </code></pre>
  
  <p>But get the following errors</p>
  
  <pre><code>    {
    "errors": [
      {
        "message": "Unknown argument \"email\" on field \"getV1User\" of type \"Query\".",
        "locations": [
          {
            "line": 2,
            "column": 13
          }
        ],
        "name": "GraphQLError"
      },
      {
        "message": "Field \"getV1User\" argument \"id\" of type \"ID!\" is required but not provided.",
        "locations": [
          {
            "line": 2,
            "column": 3
          }
        ],
        "name": "GraphQLError"
      }
    ]
  }
  </code></pre>
  
  <p>My Schema is as follows</p>
  
  <pre><code>Name        Type        Constraints 
  id          ID          NonNull Unique  
  modifiedAt  DateTime    NonNull 
  createdAt   DateTime    NonNull 
  role        String      NonNull 
  password    String      NonNull 
  email       String      NonNull Unique Indexed  
  </code></pre>
  
  <p>Thanks</p>
  
  <p>Hi</p>
  
  <p>This query solved my issue</p>
  
  <pre><code>query getUserForEmailAddressAndPassword($where: V1UserWhereArgs) {
    viewer {
      allV1Users(where: $where) {
        edges {
          node {
            email
            id
            createdAt
            password
            modifiedAt
            role
          }        
        }
      }
    }
  }
  </code></pre>
  
  <p>Along with these query variables</p>
  
  <pre><code>{"where": {"email": {"eq" : "test@test.com"}, "password": {"eq":"te2st"}}}
  </code></pre>