如何转动行转换成列（自定义旋转）

Question

我有类似如下的SQL数据库表：

Day Period Subject 

Mon 1   Ch 
Mon 2   Ph 
Mon 3   Mth 
Mon 4   CS 
Mon 5   Lab1 
Mon 6   Lab2 
Mon 7   Lab3 
Tue 1   Ph 
Tue 2   Ele 
Tue 3   Hu 
Tue 4   Ph 
Tue 5   En 
Tue 6   CS2 
Tue 7   Mth 

我想它显示如下：种类交叉表或数据透视

Day P1 P2 P3 P4 P5 P6 P7 

Mon Ch Ph Mth CS2 Lab1 Lab2 Lab3 
Tue Ph Ele Hu Ph En CS2 Mth 

的

什么是最理想的方式来做到这一点？有人可以请给我看看Sql代码吗？

Answer 1

你也许可以用旋转功能做到这一点，但我更喜欢老派的方法：

SELECT 
    dy, 
    MAX(CASE WHEN period = 1 THEN subj ELSE NULL END) AS P1, 
    MAX(CASE WHEN period = 2 THEN subj ELSE NULL END) AS P2, 
    MAX(CASE WHEN period = 3 THEN subj ELSE NULL END) AS P3, 
    MAX(CASE WHEN period = 4 THEN subj ELSE NULL END) AS P4, 
    MAX(CASE WHEN period = 5 THEN subj ELSE NULL END) AS P5, 
    MAX(CASE WHEN period = 6 THEN subj ELSE NULL END) AS P6, 
    MAX(CASE WHEN period = 7 THEN subj ELSE NULL END) AS P7 
FROM 
    Classes 
GROUP BY 
    dy 
ORDER BY 
    CASE dy 
     WHEN 'Mon' THEN 1 
     WHEN 'Tue' THEN 2 
     WHEN 'Wed' THEN 3 
     WHEN 'Thu' THEN 4 
     WHEN 'Fri' THEN 5 
     WHEN 'Sat' THEN 6 
     WHEN 'Sun' THEN 7 
     ELSE 8 
    END 

• 我改变了一些列的名称，以避免保留字

Answer 2

你可以试试...

SELECT DISTINCT Day, 
     (SELECT Subject 
      FROM my_table mt2 
      WHERE mt2.Day = mt.Day AND 
        Period = 1) AS P1, 
     (SELECT Subject 
      FROM my_table mt2 
      WHERE mt2.Day = mt.Day AND 
        Period = 2) AS P2, 
    . 
    . 
    etc 
    . 
    . 
    . 
    (SELECT Subject 
     FROM my_table mt2 
     WHERE mt2.Day = mt.Day AND 
       Period = 7) AS P7 
FROM my_table mt; 

，但我不能说我非常喜欢它。不过比没有好。

Answer 3

使用交叉适用于在单个列中以逗号分隔格式获取所有值。而不是“7”不同的列。下面的查询可用于任何列 - >排映

SELECT DISTINCT Day, [DerivedColumn] FROM <Table> A CROSS APPLY (SELECT Period + ',' FROM <Table> B WHERE A.Day = B.Day Order By Period FOR XML PATH('')) AS C (DerivedColumn) 

你会得到〔CH，PH，第M，CS2，实验室1，实验2，Lab3的在一列星期一等等......你可以用它作为查询任何特定日子的表格。

希望这有助于

Answer 4

只是柜面你想新学校的方法。 （该枢轴语句应在SQL2005 +工作，VALUES位的示例数据仅SQL2008）

WITH ExampleData AS 
(
SELECT X.* 
    FROM (VALUES 
('Mon', 1, 'Ch'), 
('Mon', 2, 'Ph'), 
('Mon', 3, 'Mth'), 
('Mon', 4, 'CS'), 
('Mon', 5, 'Lab1'), 
('Mon', 6, 'Lab2'), 
('Mon', 7, 'Lab3'), 
('Tue', 1, 'Ph'), 
('Tue', 2, 'Ele'), 
('Tue', 3, 'Hu'), 
('Tue', 4, 'Ph'), 
('Tue', 5, 'En'), 
('Tue', 6, 'CS2'), 
('Tue', 7, 'Mth') 
) AS X (Day, Period, Subject) 
) 

SELECT Day, [1] AS P1, [2] AS P2,[3] AS P3, [4] AS P4, [5] AS P5,[6] AS P6,[7] AS P7 
FROM ExampleData 
PIVOT 
( 
Max(Subject) 
FOR Period IN ([1], [2],[3],[4], [5],[6], [7]) 
) AS PivotTable; 

结果

Day P1 P2 P3 P4 P5 P6 P7 
---- ---- ---- ---- ---- ---- ---- ---- 
Mon Ch Ph Mth CS Lab1 Lab2 Lab3 
Tue Ph Ele Hu Ph En CS2 Mth 

Answer 5

with pivot_data as 
(
select [day], -- groping column 
period, -- spreading column 
subject -- aggreate column 
from pivot_tb 
) 
select [day], [1] AS P1, [2] AS P2,[3] AS P3, [4] AS P4, [5] AS P5,[6] AS P6,[7] AS P7 
from pivot_data 
pivot (max(subject) for period in ([1], [2],[3],[4], [5],[6], [7])) as p; 

Answer 6

DECLARE @TIMETABLE TABLE (
    [Day]  CHAR(3), 
    [Period] TINYINT, 
    [Subject] CHAR(5) 
) 
INSERT INTO @TIMETABLE([Day], [Period], [Subject]) 
VALUES 
    ('Mon', 1, 'Ch'), 
    ('Mon', 2, 'Ph'), 
    ('Mon', 3, 'Mth'), 
    ('Mon', 4, 'CS'), 
    ('Mon', 5, 'Lab1'), 
    ('Mon', 6, 'Lab2'), 
    ('Mon', 7, 'Lab3'), 
    ('Tue', 1, 'Ph'), 
    ('Tue', 2, 'Ele'), 
    ('Tue', 3, 'Hu'), 
    ('Tue', 4, 'Ph'), 
    ('Tue', 5, 'En'), 
    ('Tue', 6, 'CS2'), 
    ('Tue', 7, 'Mth') 

SELECT 
    [Day], 
    MAX(CASE [Period] WHEN 1 THEN [Subject] END) AS P1, 
    MAX(CASE [Period] WHEN 2 THEN [Subject] END) AS P2, 
    MAX(CASE [Period] WHEN 3 THEN [Subject] END) AS P3, 
    MAX(CASE [Period] WHEN 4 THEN [Subject] END) AS P4, 
    MAX(CASE [Period] WHEN 5 THEN [Subject] END) AS P5, 
    MAX(CASE [Period] WHEN 6 THEN [Subject] END) AS P6, 
    MAX(CASE [Period] WHEN 7 THEN [Subject] END) AS P7 
FROM @TIMETABLE 
GROUP BY [Day]