Output Values

What you can return from a query using RETURN.

HelixQL queries end with a RETURN clause. You can return bindings (variables), projected properties, aggregations, literals, or choose to return nothing at all.

Quick reference

Return Type	Syntax	Return Type	Syntax
Return a binding	RETURN users	Exclude fields	RETURN users::!{ email }
Return multiple	RETURN user, posts	Aggregation/scalar	RETURN count
Project fields	RETURN users::{ name, age }	Literal	RETURN "ok"
Only IDs	RETURN users::ID	No payload	RETURN NONE

When using the Python SDK, the output values are wrapped in an array for multiple query calls, so you will need to access the first element of the array to get the result of the first call.

Response structure

Every HelixQL response is a JSON object whose top-level keys are the binding names used in RETURN. The value for each key depends on how many elements the binding holds:

Binding selects	Example syntax	Value shape
Multiple elements	N<User>	Array of objects
Single element (by ID)	N<User>(user_id)	Single object
Traversal results	user::Out<Follows>	Array of objects
Scalar / aggregation	N<User>::COUNT	Single value

Element object shapes

Every element returned by HelixDB includes an id field (a UUID string) alongside its schema-defined properties.

Node

{ "id": "c2ca233f-...", "name": "Alice", "age": 25, "email": "[e-mail]" }

Edge — includes from and to fields referencing the connected node IDs, plus any properties defined in the Properties block of the schema.

{ "id": "a1b2c3d4-...", "from": "c2ca233f-...", "to": "d3db344g-...", "since": "2024-01-15" }

Vector — includes metadata properties defined in the schema.

{ "id": "f5e6d7c8-...", "content": "Quick brown fox", "created_at": "2024-01-15T00:00:00Z" }

When you use property projection (::{ name, age }), only the fields you list are returned — id is not included unless you explicitly request it (e.g. ::{ userID: ::ID, name }). When you use property exclusion (::!{ email }), id is still included because it is not a schema-defined property.

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Returning bindings

Return any previously bound value from your traversal.

Query

QUERY GetAllUsers() =>
    users <- N<User>
    RETURN users

Returning multiple values creates multiple top-level fields in the response, named after the variables.

Query

QUERY GetUserAndPosts(user_id: ID) =>
    user <- N<User>(user_id)
    posts <- user::Out<User_to_Post>
    RETURN user, posts

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Returning projections and properties

Use property projection to shape the returned data.

Query

QUERY FindUsers() =>
    users <- N<User>::RANGE(0, 10)
    RETURN users::{ name, age }

Return just the ID of each element:

Query

QUERY FindUserIDs() =>
    users <- N<User>::RANGE(0, 10)
    RETURN users::ID

Exclude specific properties:

Query

QUERY FindUsersNoPII() =>
    users <- N<User>::RANGE(0, 10)
    RETURN users::!{ email, location }

You can also create nested or remapped shapes in RETURN using nested mappings:

Query

QUERY FindFriends(user_id: ID) =>
    user <- N<User>(user_id)
    posts <- user::Out<User_to_Post>::RANGE(0, 20)
    RETURN user::|u|{
        userID: u::ID,
        posts: posts::{
            postID: ID,
            creatorID: u::ID,
            ..
        }
    }

See property access, remappings, and exclusion for more details.

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Returning scalars and literals

Aggregations and scalar bindings can be returned directly:

Query

QUERY CountUsers() =>
    user_count <- N<User>::COUNT
    RETURN user_count

You can also return literals (strings, numbers, booleans) when useful:

Query

QUERY DeleteCity(city_id: ID) =>
    DROP N<City>(city_id)
    RETURN "success"

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Returning nothing

For mutations or maintenance operations where you do not want a response payload, use RETURN NONE.

Query

QUERY DeleteCityQuietly(city_id: ID) =>
    DROP N<City>(city_id)
    RETURN NONE

RETURN NONE signals that the query intentionally produces no output values. This is handy to avoid sending placeholder strings like “success” when a silent acknowledgement is preferred.