SQL 服务器 - 将行转换为列（带有附加行数据）

Question

有人可以帮我解决这个问题 SQL 吗？

我希望通过以下方式将多行转换为列：id、类型、颜色、日期

挑战：我有多个列想要 preserve/be 显示在旋转的 table 上。

id | type   | color  | date      | country_code | cost
---+--------+--------+-----------+--------------+-------
1  | report | red    | 2020-09-01| US           | 1
1  | report | red    | 2020-09-01| EU           | 2
1  | report | red    | 2020-09-01| RU           | 3
1  | report | red    | 2020-09-01| AP           | 4
1  | report | blue   | 2020-09-02| US           | 5   
1  | report | blue   | 2020-09-02| EU           | 6
1  | report | blue   | 2020-09-02| RU           | 7
1  | report | blue   | 2020-09-02| AP           | 8
2  | report | green  | 2020-09-02| US           | 9
2  | report | green  | 2020-09-02| EU           | 10
2  | report | green  | 2020-09-02| RU           | 11
2  | report | green  | 2020-09-02| AP           | 12
2  | report | blue   | 2020-09-03| US           | 13
2  | report | blue   | 2020-09-03| EU           | 14
2  | report | blue   | 2020-09-03| RU           | 15
2  | report | blue   | 2020-09-03| AP           | 16

期望的输出：

id | type   | color | date       | US | EU | RU | AP
---+--------+-------+------------+----+----+----+----
1  | report | red   | 2020-09-01 | 1  | 2  | 3  | 4
1  | report | blue  | 2020-09-02 | 5  | 6  | 7  | 8
2  | report | green | 2020-09-02 | 9  | 10 | 11 | 12
2  | report | blue  | 2020-09-03 | 13 | 14 | 15 | 16

已知信息：

只有4个国家代码。
color 值将相同：id、类型、日期。

不确定什么是最 cleanest/best 的写法 SQL。

我试过

ROW_NUMBER() OVER(PARTITION BY xxx ORDER BY yyy)

和PIVOT但无法得到我想要的结果

Answer 1

我认为条件聚合可以满足您的需求：

select id, type, color, date,
       max(case when country_code = 'US' then cost end) as us,
       max(case when country_code = 'EU' then cost end) as eu,
       max(case when country_code = 'RU' then cost end) as ru,
       max(case when country_code = 'AP' then cost end) as AP
from t
group by id, type, color, date;

Answer 2

我玩了一下，觉得我明白了：

SELECT id, type, color, date, [US], [EU], [RU], [AP]
FROM
(
  SELECT id, type, color, date, country_code, cost FROM tableX
) t
PIVOT
(
  MAX(cost)
  FOR country_code IN ( [US], [EU], [RU], [AP] )
) p

SQL 服务器 - 将行转换为列（带有附加行数据）

SQL Server - Pivot Convert rows to columns (with additional row data)

sql

sql-server

pivot

unpivot

partition-by