Function agg_spec

nodedb-query/src/window/value_agg.rs:435–444

(func: &str, frame: WindowFrame, order_by: Vec<(SqlExpr, bool)>)

    }

    fn agg_spec(func: &str, frame: WindowFrame, order_by: Vec<(SqlExpr, bool)>) -> WindowFuncSpec {
        WindowFuncSpec {
            alias: format!("w_{func}"),
            func_name: func.to_string(),
            args: vec![col("v")],
            partition_by: vec![],
            order_by,
            frame,
        }
    }

    /// Drive `apply_v_aggregate` over the whole single-partition row set the
    /// same way `evaluate_window_functions_value` does (push a Null cell, then