Queries

GraphQL queries are used to fetch data from the server.

Hasura GraphQL engine auto-generates queries as part of the GraphQL schema from your Postgres schema model. It generates a range of possible queries and operators that also work with relationships defined in your SQL schema.

All tables of the database tracked by the GraphQL engine can be queried over the GraphQL endpoint. If you have a tracked table in your database, its query field is added as a nested field under the query_root root level type.

Auto-generated query field schema

For example, the auto-generated schema for the query field for a table author looks like this:

author (
  distinct_on: [author_select_column]
  where: author_bool_exp
  limit: Int
  offset: Int
  order_by:  [author_order_by!]
): [author]

See the Query API reference for the full specifications

Note

If a table is not in the public Postgres schema, the query field will be of the format <schema_name>_<table_name>.

Exploring queries

You can explore the entire schema and the available queries using the GraphiQL interface in the Hasura console.

Let’s take a look at the different queries you can run using the Hasura GraphQL engine. We’ll use examples based on a typical author/article schema for reference.