Question

我尝试编写查询，但需要一些帮助。

我有一些看起来像这样的数据：

但是，最终用户想要一个Pivot，以便数据显示如下：

我写了这段代码：

SELECT *
FROM
(
SELECT TOP 100 
Log0.sn
,CONVERT(VARCHAR(50), Log0.capture_time) AS Instant
,CONVERT(VARCHAR(50),Log0.address) + '/' + Log0.[Key] AS 'Address/Key'
,Log0.average AS Command
,Log1.average AS Actual

FROM ih3_fan_speed_log_0 Log0
LEFT JOIN ih3_fan_speed_log_01 Log1 ON Log0.sn = Log1.sn AND 
Log0.capture_time = Log1.capture_time AND Log0.address = Log1.address

WHERE Log0.sn = 'V300188' AND Log0.capture_time = '03/26/2017 13:05:00'
) Src

pivot
(
  MAX(sn)
  for Instant in ([1], [2], [3], [4])
) piv;

但是回归：

我的问题是：

1）为什么我的Pivot没有工作？ 2）甚至可以用Pivot做我需要的东西吗？

感谢您的帮助。

根据请求，这是数据：

sn  Instant Address/Key Command Actual
V300188     Mar 26 2017  1:05PM 1/EF-1  99.23   99.24
V300188     Mar 26 2017  1:05PM 2/EF-2  99.02   99.04
V300188     Mar 26 2017  1:05PM 3/EF-3  100 0
V300188     Mar 26 2017  1:05PM 4/EF-4  100 100
V300188     Mar 26 2017  1:05PM 41/MUA-1    74.58   74.58
V300188     Mar 26 2017  1:05PM 51/0-10VDC  74.58   74.58

以下是结果集：

Address/Key Command Actual  1   2   3   4
1/EF-1  99.23   99.24   NULL    NULL    NULL    NULL
2/EF-2  99.02   99.04   NULL    NULL    NULL    NULL
3/EF-3  100 0   NULL    NULL    NULL    NULL
4/EF-4  100 100 NULL    NULL    NULL    NULL
41/MUA-1    74.58   74.58   NULL    NULL    NULL    NULL
51/0-10VDC  74.58   74.58   NULL    NULL    NULL    NULL

Answer 1

以下是如何利用动态交叉表来完成此类事情的方法。 Jeff Moden在这里有一篇很棒的文章解释这种技术。 http://www.sqlservercentral.com/articles/Crosstab/65048/

if OBJECT_ID('tempdb..#Something') is not null
    drop table #Something

create table #Something
(
    sn varchar(10)
    , Instant datetime
    , [Address/Key] varchar(20)
    , Command numeric(7,2)
    , Actual numeric(7,2)
)

insert #Something
select 'V300188', 'Mar 26 2017  1:05PM', '1/EF-1', 99.23, 99.24 union all
select 'V300188', 'Mar 26 2017  1:05PM', '2/EF-2',  99.02, 99.04 union all
select 'V300188', 'Mar 26 2017  1:05PM', '3/EF-3', 100, 0 union all
select 'V300188', 'Mar 26 2017  1:05PM', '4/EF-4', 100, 100 union all
select 'V300188', 'Mar 26 2017  1:05PM', '41/MUA-1', 74.58, 74.58 union all
select 'V300188', 'Mar 26 2017  1:05PM', '51/0-10VDC', 74.58,74.58

declare @MaxCols int

declare @StaticPortion nvarchar(2000) = 
    'with OrderedResults as
    (
        select *, ROW_NUMBER() over(partition by sn order by instant) as RowNum
        from #Something
    )
    select sn, instant';

declare @DynamicPortion nvarchar(max) = '';
declare @FinalStaticPortion nvarchar(2000) = ' from OrderedResults Group by sn, instant order by sn';

with E1(N) AS (select 1 from (values (1),(1),(1),(1),(1),(1),(1),(1),(1),(1))dt(n)),
E2(N) AS (SELECT 1 FROM E1 a, E1 b), --10E+2 or 100 rows
E4(N) AS (SELECT 1 FROM E2 a, E2 b), --10E+4 or 10,000 rows max
cteTally(N) AS 
(
    SELECT  ROW_NUMBER() OVER (ORDER BY (SELECT NULL)) FROM E4
)

select @DynamicPortion = @DynamicPortion + 
    ', MAX(Case when RowNum = ' + CAST(N as varchar(6)) + ' then [Address/Key] end) as address' + CAST(N as varchar(6)) + CHAR(10) +
    ', MAX(Case when RowNum = ' + CAST(N as varchar(6)) + ' then Command end) as Command' + CAST(N as varchar(6)) + CHAR(10) +
    ', MAX(Case when RowNum = ' + CAST(N as varchar(6)) + ' then Actual end) as Actual' + CAST(N as varchar(6)) + CHAR(10)
from cteTally t
where t.N <= 
(
    select top 1 Count(*)
    from #Something
    group by sn, instant
    order by COUNT(*) desc
)

select @StaticPortion + @DynamicPortion + @FinalStaticPortion

declare @SqlToExecute nvarchar(max) = @StaticPortion + @DynamicPortion + @FinalStaticPortion;
exec sp_executesql @SqlToExecute

Answer 2

动态数据透视的另一种选择

扭曲是最终结果中的非独特/重复列。如您所见，这是通过简单的替换（x3）解决的。

Declare @SQL varchar(max) = Stuff((Select Distinct ','+QuoteName(concat('A',ColGrp)) 
                                                  +','+QuoteName(concat('B',ColGrp)) 
                                                  +','+QuoteName(concat('C',ColGrp)) 
                                    From (Select Distinct ColGrp=Row_Number() over (Partition By sn,Instant Order by [Address/Key]) From YourTable ) A  
                                    Order By 1 
                                    For XML Path('')),1,1,'') 

Select  @SQL = '
Select [SN],[Instant],' + replace(replace(replace(@SQL,'[A','[Address/Key]=[A'),'[C','[Actual]=[C'),'[B','[Command]=[B') + '
From (
        Select [SN]
              ,[Instant]
              ,[Col]     = Concat(B.Prefix,RN  )
              ,B.Value
        From (Select *,RN=Row_Number() over (Partition By sn,Instant Order by [Address/Key]) From YourTable) A
        Cross Apply (values (''A'',[Address/Key])
                            ,(''B'',cast(Command as varchar(25)))
                            ,(''C'',cast(Actual as varchar(25)))
                    ) B (PreFix,Value)
     ) A
 Pivot (max([Value]) For [Col] in (' + @SQL + ') ) p'
--Print @SQL
Exec(@SQL);

<强>返回

编辑 - 如果它有助于可视化

生成的SQL看起来像这样

Select [SN],[Instant],[Address/Key]=[A1],[Command]=[B1],[Actual]=[C1],[Address/Key]=[A2],[Command]=[B2],[Actual]=[C2],[Address/Key]=[A3],[Command]=[B3],[Actual]=[C3],[Address/Key]=[A4],[Command]=[B4],[Actual]=[C4],[Address/Key]=[A5],[Command]=[B5],[Actual]=[C5],[Address/Key]=[A6],[Command]=[B6],[Actual]=[C6]
From (
        Select [SN]
              ,[Instant]
              ,[Col]     = Concat(B.Prefix,RN  )
              ,B.Value
        From (Select *,RN=Row_Number() over (Partition By sn,Instant Order by [Address/Key]) From YourTable) A
        Cross Apply (values ('A',[Address/Key])
                           ,('B',cast(Command as varchar(25)))
                           ,('C',cast(Actual as varchar(25)))
                    ) B (PreFix,Value)
     ) A
 Pivot (max([Value]) For [Col] in ([A1],[B1],[C1],[A2],[B2],[C2],[A3],[B3],[C3],[A4],[B4],[C4],[A5],[B5],[C5],[A6],[B6],[C6]) ) p

SQL Pivot可能用于此数据集吗？

2 个答案: