Question

这是我的常规选择查询：

SELECT [category], [price], [company]
FROM [prices] 
INNER JOIN [company] AS [co] ON [co].[company] = [pr].[company]
WHERE [co].[id] IN (1,2,3);

结果是：

category | price | company 
---------+-------+-------------
 Srv     | 1200  | CoA
 Srv     | 2800  | CoB
 EQ      | 5400  | CoA
 Deduc   | 400   | CoA
 Deduc   | 150   | CoB

我需要这个结果：

PriceASrv  | PriceBSrv | PriceAEQ | PriceBEQ | PriceADeduc | PriceBDeduc
-----------+-----------+----------+----------+-------------+-------------
 1200      | 2800      | 5400     | NULL     | 400         | 150

看来我需要两次PIVOT，对吗？有没有人有任何想法？

Answer 1

不，您不需要两次转动，但在以下情况下您可能需要动态查询：

可以有两家以上的公司，或者
您的公司名称可以更改，或者
您的类别可能会发生变化

如果这三个条件都是假的，则以下任一查询都可以起作用：

DECLARE @T TABLE (Category VARCHAR(10), Price INT, Company CHAR(3));
INSERT @T VALUES
    ('Srv', 1200, 'CoA'),
    ('Srv', 2800, 'CoB'),
    ('EQ', 5400, 'CoA'),
    ('Deduc', 400, 'CoA'),
    ('Deduc', 150, 'CoB');

-- With PIVOT
SELECT *
FROM (
    SELECT CatCom = 'Price' + RIGHT(Company, 1) + Category,
           Price 
    FROM @T) AS T
PIVOT (MAX(Price) FOR CatCom IN ([PriceASrv], [PriceBSrv], [PriceAEQ], [PriceBEQ], [PriceADeduc], [PriceBDeduc])) AS P

-- With CASE aggregation
SELECT PriceASrv = MAX(CASE WHEN Category = 'Srv' AND Company = 'CoA' THEN Price END),
       PriceBSrv = MAX(CASE WHEN Category = 'Srv' AND Company = 'CoB' THEN Price END),
       PriceAEQ = MAX(CASE WHEN Category = 'EQ' AND Company = 'CoA' THEN Price END),
       PriceBEQ = MAX(CASE WHEN Category = 'EQ' AND Company = 'CoB' THEN Price END),
       PriceADeduc = MAX(CASE WHEN Category = 'Deduc' AND Company = 'CoA' THEN Price END),
       PriceBDeduc = MAX(CASE WHEN Category = 'Deduc' AND Company = 'CoB' THEN Price END)
FROM @T;

如果这三个条件中的任何一个都是真的，那么您可能需要一个动态查询（基本上可以修改上述任一查询以满足您的需求）。

Answer 2

不，你不需要两次PIVOT。见下面的查询。如果您不知道可能存在的公司数量，您可以转换为动态支点

Select * from 
(
Select 
  [data]='Price' + RIGHT([company],1) +[category] , 
  [price]
FROM [prices] 
INNER JOIN [company] as [co] On [co].[company] = [pr].[company]
WHERE [co].[id] In (1,2,3))src
PIVOT
( 
MAX([price]) FOR [data] in (PriceASrv,PriceBSrv,PriceAEQ,PriceBEQ,PriceADeduc,PriceBDeduc)
)p

<强> see working demo

在sql查询中将行转换为列的正确方法

2 个答案: