枢轴，也得到排名

Question

我正在尝试编写一个可以透视并在一行中获取其排名顺序的 SQL。不知道怎么做。

例：

旋转area但也获得cost的排名(最昂贵的顺序(

table name: aaa
entity_id | entity_type | datetime   | area | cost
----------+-------------+------+-----+------+-----
123       | ITEM        | 2020-01-01 | US   | 8
123       | ITEM        | 2020-01-01 | AP   | 7
123       | ITEM        | 2020-01-01 | EU   | 6
123       | ITEM        | 2020-01-02 | US   | 1
123       | ITEM        | 2020-01-02 | AP   | 2
123       | ITEM        | 2020-01-02 | EU   | 3
888       | BOX         | 2020-01-01 | US   | 8
888       | BOX         | 2020-01-01 | AP   | 7
888       | BOX         | 2020-01-01 | EU   | 6
888       | BOX         | 2020-01-02 | US   | 1
888       | BOX         | 2020-01-02 | AP   | 2
888       | BOX         | 2020-01-02 | EU   | 3

我想要的是：

entity_id | entity_type | datetime   | US | AP | EU | US_rank | AP_rank | EU_rank
----------+-------------+------------+----+----+----+---------+---------+---------
123       | ITEM        | 2020-01-01 | 8  | 7  | 6  | 1       | 2       | 3
123       | ITEM        | 2020-01-02 | 8  | 7  | 6  | 3       | 2       | 1
888       | BOX         | 2020-01-01 | 8  | 7  | 6  | 1       | 2       | 3
888       | BOX         | 2020-01-02 | 8  | 7  | 6  | 3       | 2       | 1

目前，我只知道如何转向。不确定如何获得"排名"部分

SELECT  
p.entity_id, p.entity_type, p.[datetime], p.[US], p.[AP], p.[EU]
FROM
aaa as a
PIVOT
(
MAX(cost)
FOR area IN ([US], [AP], [EU])
) p
(which returns)
entity_id | entity_type | datetime   | US | AP | EU 
----------+-------------+------------+----+----+----
123       | ITEM        | 2020-01-01 | 8  | 7  | 6  
123       | ITEM        | 2020-01-02 | 8  | 7  | 6  
888       | BOX         | 2020-01-01 | 8  | 7  | 6  
888       | BOX         | 2020-01-02 | 8  | 7  | 6  

我想我需要在转向之前将其添加到某个地方，但不确定之后该怎么做

ranking = ROW_NUMBER() OVER(PARTITION BY entity_id, entity_type, [datetime] ORDER BY cost DESC)

(我不介意使用RANK或ROW_NUMBER来解决这个问题(

Answer 1

使用条件聚合：

select entity_id, entity_type, datetime,
max(case when area = 'US' then cost end) as us,
max(case when area = 'AP' then cost end) as ap,
max(case when area = 'EU' then cost end) as eu,
max(case when area = 'US' then rnk end) as us_rank,
max(case when area = 'AP' then rnk end) as ap_rank,
max(case when area = 'EU' then rnk end) as eu_rank
from (select s.*,
rank() over (partition by entity_id, entity_type, datetime 
order by cost desc
) as rnk
from aaa a
) a
group by entity_id, entity_type, datetime