如何将行旋转到列中(自定义旋转)

I have a Sql Database table similar to the following:

我有一个类似于以下的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

I would like it displayed as follows: Kind of crosstab or Pivot

我希望它显示如下:一种交叉表或枢轴。

Day   P1   P2   P3   P4   P5   P6   P7

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

What would be the ideal way to do it? Can someone please show me the Sql code please?

理想的方法是什么?能给我看看Sql代码吗?

6 个解决方案

#1

You could probably do it with the PIVOT function, but I prefer the old school method:

你可以用主函数来做，但我更喜欢老式的方法

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

I changed some column names to avoid reserved words
我更改了一些列名以避免保留词

#2

Just incase you do want the new school method. (The Pivot statement should work in SQL2005+, the VALUES bit for the example data only SQL2008)

以防你想要新的学校教育方法。(Pivot语句应该在SQL2005+中使用，而示例数据的值位仅在SQL2008中使用)

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;

Result

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

#3

You could try...

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;

but I can't say I like it very much. Better than nothing, though.

但我不能说我很喜欢它。不过,总比没有好。

#4

Use cross apply to get all the values in a comma delimted format in a single column. instead of "7" different columns. The following query can be used for any column-> row mapping

使用cross apply在一列中以逗号分隔格式获取所有值。而不是“7”不同的列。以下查询可用于任何列——>行映射

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)

You will get [Ch,Ph,Mth,CS2,Lab1,Lab2,Lab3] in one column for Mon and so on ... You could use this as a table to query for any particular Day.

你会得到[Ch,Ph,Mth,CS2,Lab1,Lab2,Lab3]在Mon的一个列中，等等……您可以将其用作查询任何特定日期的表。

Hope this helps

希望这有助于

#5

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]

#6

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;

#1