Struct AggregationProjector 

pub struct AggregationProjector;

Aggregation result projector

Implementations

impl AggregationProjector

pub fn project( rows: Vec<HashMap<String, Value>>, _plan: &AggregationPlan, ) -> Result<Value>

Project SQL aggregate results to GraphQL JSON.

Arguments

• rows - SQL result rows as HashMaps
• plan - Aggregation execution plan (for metadata)

Returns

GraphQL-compatible JSON response

Example

let rows = vec![
    hashmap!{
        "category" => json!("Electronics"),
        "count" => json!(42),
        "revenue_sum" => json!(5280.50)
    }
];

let result = AggregationProjector::project(rows, &plan)?;
// result: [{"category": "Electronics", "count": 42, "revenue_sum": 5280.50}]

pub fn wrap_in_data_envelope(projected: Value, query_name: &str) -> Value

Wrap projected results in GraphQL data envelope.

Arguments

• projected - Projected result array
• query_name - GraphQL query field name (e.g., “sales_aggregate”)

Returns

Complete GraphQL response with {"data": {...}} wrapper

Example

let projected = json!([{"count": 42}]);
let response = AggregationProjector::wrap_in_data_envelope(projected, "sales_aggregate");
// response: {"data": {"sales_aggregate": [{"count": 42}]}}

pub fn project_single( row: HashMap<String, Value>, _plan: &AggregationPlan, ) -> Result<Value>

Project a single aggregate result (no GROUP BY).

When there’s no GROUP BY, the result is a single object, not an array.

Example

let row = hashmap!{"count" => json!(100), "revenue_sum" => json!(5000.0)};
let result = AggregationProjector::project_single(row, &plan)?;
// result: {"count": 100, "revenue_sum": 5000.0}