Function extract_grouping_calls

nodedb-sql/src/planner/aggregate.rs:272–286

Scan the SELECT projection for `GROUPING(col)` calls and return synthetic `AggregateExpr` entries so the executor can compute the per-set bitmask value. For `GROUPING(col)`, the canonical index of `col` in `canonical_keys` is encoded into the `field` of the resulting `AggregateExpr` (as a decimal string). The executor reads this index and checks the grouping-set bitmask at run time.

(
    items: &[ast::SelectItem],
    canonical_keys: &[SqlExpr],
)

/// encoded into the `field` of the resulting `AggregateExpr` (as a decimal string).
/// The executor reads this index and checks the grouping-set bitmask at run time.
fn extract_grouping_calls(
    items: &[ast::SelectItem],
    canonical_keys: &[SqlExpr],
) -> Result<Vec<AggregateExpr>> {
    let mut out = Vec::new();
    for item in items {
        let (expr, alias): (&ast::Expr, String) = match item {
            ast::SelectItem::UnnamedExpr(expr) => (expr, format!("{expr}")),
            ast::SelectItem::ExprWithAlias { expr, alias } => (expr, normalize_ident(alias)),
            _ => continue,
        };
        collect_grouping_from_expr(expr, &alias, canonical_keys, &mut out)?;
    }
    Ok(out)
}

/// Recursively collect `GROUPING(col)` calls from an expression.
fn collect_grouping_from_expr(