SQL：不进行汇总或加入就按组排序

Question

我需要计算数据集中各组的总和（值），然后根据该总和对各组进行排名。

这是示例数据集和结果。我想知道哪个CYL组的总mpg最高（我知道这是荒谬的结果！）以及CYL组的排名。

数据：

| model               | mpg  | cyl | gear | 
|---------------------|------|-----|------| 
| Mazda RX4           | 21   | 6   | 4    | 
| Mazda RX4 Wag       | 21   | 6   | 4    | 
| Datsun 710          | 22.8 | 4   | 4    | 
| Hornet 4 Drive      | 21.4 | 6   | 3    | 
| Hornet Sportabout   | 18.7 | 8   | 3    | 
| Valiant             | 18.1 | 6   | 3    | 
| Duster 360          | 14.3 | 8   | 3    | 
| Merc 240D           | 24.4 | 4   | 4    | 
| Merc 230            | 22.8 | 4   | 4    | 
| Merc 280            | 19.2 | 6   | 4    | 
| Merc 280C           | 17.8 | 6   | 4    | 
| Merc 450SE          | 16.4 | 8   | 3    | 
| Merc 450SL          | 17.3 | 8   | 3    | 
| Merc 450SLC         | 15.2 | 8   | 3    | 
| Cadillac Fleetwood  | 10.4 | 8   | 3    | 
| Lincoln Continental | 10.4 | 8   | 3    | 
| Chrysler Imperial   | 14.7 | 8   | 3    | 
| Fiat 128            | 32.4 | 4   | 4    | 
| Honda Civic         | 30.4 | 4   | 4    | 
| Toyota Corolla      | 33.9 | 4   | 4    | 
| Toyota Corona       | 21.5 | 4   | 3    | 
| Dodge Challenger    | 15.5 | 8   | 3    | 
| AMC Javelin         | 15.2 | 8   | 3    | 
| Camaro Z28          | 13.3 | 8   | 3    | 
| Pontiac Firebird    | 19.2 | 8   | 3    | 
| Fiat X1-9           | 27.3 | 4   | 4    | 
| Porsche 914-2       | 26   | 4   | 5    | 
| Lotus Europa        | 30.4 | 4   | 5    | 
| Ford Pantera L      | 15.8 | 8   | 5    | 
| Ferrari Dino        | 19.7 | 6   | 5    | 
| Maserati Bora       | 15   | 8   | 5    | 
| Volvo 142E          | 21.4 | 4   | 4    | 

这是期望的输出：

| cyl | gear | SUM([MPG]) | sum_mpg_by_group  | RANK | 
|-----|------|------------|-------------------|------| 
| 4   | 3    | 21.5       | 293.3             | 1    | 
| 4   | 5    | 56.4       | 293.3             | 1    | 
| 4   | 4    | 215.4      | 293.3             | 1    | 
| 6   | 5    | 19.7       | 138.2             | 3    | 
| 6   | 3    | 39.5       | 138.2             | 3    | 
| 6   | 4    | 79         | 138.2             | 3    | 
| 8   | 5    | 30.8       | 211.4             | 2    | 
| 8   | 3    | 180.6      | 211.4             | 2    | 

要求：

这应该在没有with语句或joins的情况下完成-我知道是否可以使用它们，但是出于性能和简洁的原因，我想探索没有它们的选项。

换句话说，有一种无需使用联接即可基于GROUPED SUM获得组的RANK吗？

以下内容将我带到了那里，但很显然RANK（）语句失败了，所以我只缺少最后一列。

-- Non working query

select cyl
    , gear
    , sum(mpg) as sum_mpg
    , sum(sum(mpg)) over (PARTITION BY cyl) as sum_mpg_by_group
  --, rank() over (group by model order by sum(mpg) desc) as RANK
from sample_data_mtcars
group by cyl, gear

Answer 1

这听起来像是聚合和dense_rank()：

select s.*,
       dense_rank() over (order by sum_mpg_group desc) as ranking
from (select cyl, gear, sum(mpg) as sum_mpg,
             sum(sum(mpg)) over (partition by cyl) as sum_mpg_group
      from sample_data_mtcars
      group by cyl, gear
     ) s