SQL Pivot（我做错了什么）

Question

我有一个看起来如下的表，想要转动它

Acct_ID Dec_DT                  Dec_rsn
1       2013-04-01 00:00:00.000 k
1       2013-01-01 00:00:00.000 x
1       2013-01-02 00:00:00.000 y
1       2013-10-02 00:00:00.000 z
2       2013-01-01 00:00:00.000 x
2       2013-01-01 00:00:00.000 y
2       2013-11-01 00:00:00.000 x
3       2013-12-01 00:00:00.000 z
4       2013-01-01 00:00:00.000 z
5       2013-11-01 00:00:00.000 y
5       2013-02-01 00:00:00.000 z
6       2013-03-01 00:00:00.000 x
1       2013-05-21 00:00:00.000 x

我有以下代码但不能正常工作....

DECLARE 
    @cols AS NVARCHAR(MAX),
    @query  AS NVARCHAR(MAX)


SET @cols =
STUFF((SELECT distinct ',' + QUOTENAME(ROW_NUMBER()OVER(PARTITION BY ACCT_ID ORDER BY Dec_dt DESC)) as DecRsn
            FROM #test  c
            FOR XML PATH(''), TYPE
            ).value('.', 'NVARCHAR(MAX)') 
        ,1,1,'')
set @query = 'Select Acct_ID, ' + @cols + ' from 
    (
        SELECT  
          Acct_ID, 
          Dec_DT, 
          Dec_rsn
        from #test

     )x

    pivot
    (
      max(Dec_DT)
    for Dec_rsn in (' + @cols + ')
    )p '

execute(@query)

Answer 1

使用以下查询来解决您的问题：

DECLARE 
    @cols AS NVARCHAR(MAX),
    @query  AS NVARCHAR(MAX)

SET @cols =
STUFF((SELECT distinct ',' + QUOTENAME(ROW_NUMBER()OVER(PARTITION BY Acct_ID ORDER BY Dec_dt DESC)) as DecRsn
            FROM tbl  c
            FOR XML PATH(''), TYPE
            ).value('.', 'NVARCHAR(MAX)') 
        ,1,1,'')

set @query = 'Select Dec_rsn,' + @cols + ' from 
    (
        SELECT  
          Acct_ID, 
          Dec_DT, 
          Dec_rsn
        from #test) x
    pivot
    (
      max(Dec_DT)
    for Acct_ID in (' + @cols + ')
    )p '

 print @query

 execute(@query)

Answer 2

declare @stmt nvarchar(max)

select @stmt = isnull(@stmt + ', ', '') + Dec_rsn
from (select distinct Dec_rsn from Table1) as a

select @stmt = '
    select Acct_ID, ' + @stmt + '
    from Table1 as x
    pivot (
        max(Dec_DT) for Dec_rsn in (' + @stmt + ')
    )  as p'

exec sp_executesql @stmt = @stmt

<强> sql fiddle demo

更新

declare @stmt nvarchar(max)

select @stmt = isnull(@stmt + ', ', '') + Dec_rsn
from (select distinct 'Dec_rsn' + cast(dense_rank() over(order by Dec_rsn) as nvarchar(max)) as Dec_rsn from Table1) as a

select @stmt = '
    select Acct_ID, ' + @stmt + '
    from (
        select
            Acct_ID, Dec_DT, 
            ''Dec_rsn'' + cast(dense_rank() over(order by Dec_rsn) as nvarchar(max)) as Dec_rsn
        from Table1
    ) as a
    pivot (
        max(Dec_DT) for Dec_rsn in (' + @stmt + ')
    ) as p'

exec sp_executesql @stmt = @stmt

<强> sql fiddle demo

更新2

declare @stmt nvarchar(max)

select @stmt = isnull(@stmt + ', ', '') + Dec_rsn
from (select distinct 'Dec_rsn' + cast(row_number() over(partition by Acct_ID order by Dec_DT) as nvarchar(max)) as Dec_rsn from Table1) as a

select @stmt = '
    select Acct_ID, ' + @stmt + '
    from (
        select
            Acct_ID, Dec_rsn, 
            ''Dec_rsn'' + cast(row_number() over(partition by Acct_ID order by Dec_DT) as nvarchar(max)) as rn
        from Table1
    ) as a
    pivot (
        max(Dec_rsn) for rn in (' + @stmt + ')
    ) as p'

exec sp_executesql @stmt = @stmt

<强> sql fiddle demo