hasura/graphql-engine · error · InternalDeveloperError

The aggregation function {aggregation_function} operating ov

Error message

The aggregation function {aggregation_function} operating over the {aggregate_operand_type} type is missing a data connector mapping for {data_connector_name}

What it means

An aggregation function (e.g. avg, sum) used in a query has no mapping for the given data connector for the operand type. Each connector declares which aggregation functions it supports per type; using an unsupported combination fails at IR resolution.

Source

Thrown at v3/crates/graphql/ir/src/error.rs:222

    #[error("The field '{field_name}' was not found on object type '{object_type_name}'")]
    ObjectTypeFieldNotFound {
        field_name: FieldName,
        object_type_name: Qualified<CustomTypeName>,
    },

    #[error("{0}")]
    RelationshipFieldMappingError(#[from] plan::RelationshipFieldMappingError),

    #[error(
        "Argument mapping not found for the argument {argument_name:} while executing the relationship {relationship_name:}"
    )]
    ArgumentMappingNotFoundForRelationship {
        relationship_name: RelationshipName,
        argument_name: ArgumentName,
    },

    #[error(
        "The aggregation function {aggregation_function} operating over the {aggregate_operand_type} type is missing a data connector mapping for {data_connector_name}"
    )]
    DataConnectorAggregationFunctionNotFound {
        aggregate_operand_type: QualifiedTypeName,
        aggregation_function: AggregationFunctionName,
        data_connector_name: Qualified<DataConnectorName>,
    },

    #[error(
        "A field ({field_name}) with an AggregatableField annotation was found on a scalar-typed ({aggregate_operand_type}) operand's selection set"
    )]
    AggregatableFieldFoundOnScalarTypedOperand {
        field_name: FieldName,
        aggregate_operand_type: QualifiedTypeName,
    },

    #[error(
        "The aggregation function {aggregation_function} was used on the model object type and not on a model field. Aggregation functions operate on columns, not rows"

View on GitHub (pinned to 724551b9ae)

Solutions

1. Use an aggregation function the connector supports for that operand type
2. Cast or model the column as a type the connector can aggregate (e.g. numeric)
3. Extend the connector's aggregation mappings if you own the connector
4. Perform the aggregation client-side or via a custom command if unsupported

Example fix

# before
query { songs_aggregate { agg { avg { release_year } } } }
# after
query { songs_aggregate { agg { max { release_year } } } }

// Check connector capabilities before using an aggregation
const supported = connectorCapabilities.aggregationsFor('avg', 'date');
if (!supported) useFallback();

const canAggregate = (caps, fn, type) =>
  caps.aggregation_functions?.some(f => f.name === fn && foperand_types?.includes(type));

// On this error, retry with a supported function (max/min) or fetch rows and aggregate client-side

When it happens

Trigger: Using avg() on a column whose type the connector (e.g. a specific database) cannot aggregate; querying through a connector that lacks an aggregation mapping for that function/type pair; switching data sources to one with narrower aggregation support.

Common situations: Using date/time or string columns with numeric aggregation functions; expecting Postgres-level aggregation support from a limited connector; upgrading a connector that dropped support for a function.

Related errors

• error from data source: {}
• invalid connector error: {0}
• invalid connector error with status {status} and {content}
• A field ({field_name}) with an AggregatableField annotation
• The aggregation function {aggregation_function} was used on

AI-assisted analysis of hasura/graphql-engine@724551b9ae (2026-08-28). Data as JSON: /api/errors/ef8f019e5c735f78. Report an issue: GitHub.