SQL Server : how to transpose rows into columns

Question

在 T-SQL 中，我试图将某些行的值转置为列。
初始表:

Project | Machine | Value
-------------------------
A   X   100
A   Y   99
A   Z   98
A   W   97
B   X   97
B   Y   96
B   W   95
C   X   95
C   Z   94

我想要的结果:

Project     MX  MY  MZ  MW
-----------------------------
A           100 99  98  97
B            97 96   0  95
C            95  0  94   0

我已经创建了测试代码:

CREATE TABLE Company (project char(1), machine char(1), cost int)
GO

INSERT INTO Company 
VALUES ('A', 'X', 100), ('A', 'Y', 99), ('A', 'Z', 98),
       ('A', 'W', 97), ('B', 'X', 97), ('B', 'Y', 96),
       ('B', 'W', 95), ('C', 'X', 95), ('C', 'Z', 94);

我的数据透视查询:

SELECT
    project, 'X', 'Y', 'Z', 'W'
FROM
    (SELECT 
         project, machine, cost 
     FROM 
         Company) p
PIVOT
    (MAX(cost)
        FOR machine IN ('X', 'Y', 'Z', 'W') AS  pvt

我收到此错误:

Incorrect syntax near ''X''

我的数据透视查询错了吗？

提前致谢

Answer 1

如果你的机器有限，那么我会做条件聚合而不是 PIVOT :

SELECT Project,
       MAX(CASE WHEN machine = 'X' THEN cost END) AS MX,
       MAX(CASE WHEN machine = 'Y' THEN cost END) AS MY,
       MAX(CASE WHEN machine = 'Z' THEN cost END) AS MZ,
       MAX(CASE WHEN machine = 'W' THEN cost END) AS MW
FROM Company c
GROUP BY Project;

如果你想和 PIVOT一起去，然后我将修复缺少右括号的语法错误:

SELECT * 
FROM (SELECT project, machine, cost 
      FROM Company 
     ) AS p PIVOT
     (MAX(cost)
      FOR machine IN ([X], [Y], [Z], [W]) 
     ) AS pvt;

笔记 :

不要使用单引号作为列名，而是使用方括号。