Search and Filtering - Graphql

Documentation
1

Queries generated for a GraphQL type allow you to generate a single of list of objects for a type.

Get a single object

Fetch the title, text and datePublished for a post with id 0x1.

query {
  getPost(id: "0x1") {
    title
    text
    datePublished
  }
}

Fetching nested linked objects, while using get queries is also easy. This is how you would fetch the authors for a post and their friends.

query {
  getPost(id: "0x1") {
    id
    title
    text
    datePublished
    author {
      name
      friends {
        name
      }
    }
  }
}

While fetching nested linked objects, you can also apply a filter on them.

Example - Fetching author with id 0x1 and their posts about GraphQL.

query {
  getAuthor(id: "0x1") {
    name
    posts(filter: {
      title: {
        allofterms: "GraphQL"
      }
    }) {
      title
      text
      datePublished
    }
  }
}

If your type has a field with @id directive on it, you can also fetch objects using that.

Example: To fetch a user’s name and age by userID which has @id directive.

Schema

type User {
    userID: String! @id
    name: String!
    age: String
}

Query

query {
  getUser(userID: "0x2") {
    name
    age
  }
}

Query list of objects

Fetch the title, text and and datePublished for all the posts.

query {
  queryPost {
    id
    title
    text
    datePublished
  }
}

Fetching a list of posts by their ids.

query {
  queryPost(filter: {
    id: ["0x1", "0x2", "0x3", "0x4"],
  }) {
    id
    title
    text
    datePublished
  }
}

You also filter the posts by different fields in the Post type which have a @search directive on them. To only fetch posts which GraphQL in their title and have a score > 100, you can run the following query.

query {
  queryPost(filter: {
    title: {
      anyofterms: "GraphQL"
    },
    and: {
      score: {
        gt: 100
      }
    }
  }) {
    id
    title
    text
    datePublished
  }
}

You can also filter nested objects while querying for a list of objects.

Example - To fetch all the authors whose name have Lee in them and theircompleted posts with score greater than 10.

query {
  queryAuthor(filter: {
    name: {
      anyofterms: "Lee"
    }
  }) {
    name
    posts(filter: {
      score: {
        gt: 10
      },
      and: {
        completed: true
      }
    }) {
      title
      text
      datePublished
    }
  }
}
This is a companion discussion topic for the original entry at https://dgraph.io/docs/graphql/queries/search-filtering/
2

If I run the “Query list of objects” example in Ratel console:

query {
  queryPost {
    id
    title
    text
    datePublished
  }
}

I get the following error:

Error Name: t

Message: line 2 column 12: Expected Left round brackets. Got: lex.Item [6] "{" at 2:12

Raw Error:

{
  "name": "t",
  "url": "http://localhost:8080/query?timeout=20s&debug=true&ro=true&be=true",
  "errors": [
    {
      "message": "line 2 column 12: Expected Left round brackets. Got: lex.Item [6] \"{\" at 2:12",
      "extensions": {
        "code": "ErrorInvalidRequest"
      }
    }
  ]
}
3

You are trying to run GraphQL in ratel that only supports DQL. See this post from a community member if you are new to Dgraph

FYI: The documentation categories here on discuss are not closely monitored by the core team. For better support create a new topic in Users/Dgraph or Users/GraphQL

1 Like