Implement aggregate grouping for GraphQL Interface as outlined by NDC Spec

[olmohake]

component

c/v3-ndc-postgres

Is your proposal related to a problem?

The current implementation of the Hasura NDC Postgres connector lacks support for aggregate groups, which are defined in the NDC connector specifications. This is a major obstacle when implementing data platforms and interactive user interfaces for statistical datasets, as these rely heavily on aggregation and grouping operations to produce meaningful insights.

Provide a clear and concise description of what you want to happen.

Extend the connector’s query translation layer to generate SQL GROUP BY statements based on NDC Spec aggregate group definitions.

Describe alternatives you've considered

unclear

[hgiasac]

Hi @olmohake,

Aggregate groups are already supported. However, it's only available on the SQL layer at this moment.
We have rewritten the universal connector for all relational databases here. It is listed in the DDN CLI with this name postgres-promptql.

Upcoming features will be supported on that connector. The Rust PostgreSQL connector is still maintained, but we won't spend efforts to add more features to it.

[olmohake]

Is this intended to be used in non–PromptQL / GraphQL API–oriented projects as well?
From what I’ve seen in the documentation, postgres-promptql doesn’t support relations (likely because PromptQL can handle those through plain SQL joins) or mutations. If that’s the case, it seems that aggregate groups are supported, but they come with significant drawbacks in a GraphQL API — such as losing the ability to query data from related tables.

[hgiasac]

Is this intended to be used in non–PromptQL / GraphQL API–oriented projects as well?

We may support it on the GraphQL spec, but it isn't prioritized yet.

From what I’ve seen in the documentation, postgres-promptql doesn’t support relations (likely because PromptQL can handle those through plain SQL joins) or mutations. If that’s the case, it seems that aggregate groups are supported, but they come with significant drawbacks in a GraphQL API — such as losing the ability to query data from related tables.

Relationship and mutation are already supported. README docs aren't up to date.