在 sql server 中透视一个固定的多列表

Question

我有一张表，我需要为报告服务进行数据透视：

DateCreated Rands   Units   Average Price   Success %   Unique Users
-------------------------------------------------------------------------
2013-08-26  0       0       0               0              0
2013-08-27  0       0       0               0              0
2013-08-28  10      2       5               100            1
2013-08-29  12      1       12              100            1
2013-08-30  71      9       8               100            1
2013-08-31  0       0       0               0              0
2013-09-01  0       0       0               0              0

换句话说，我需要在行中有兰特、单位、平均价格等，而日期作为列。

我已经阅读了各种示例，但我似乎无法正确理解。 任何帮助将不胜感激！

Answer 1

这个会做你想做的，但你必须指定所有的日期

select
   c.Name,
   max(case when t.DateCreated = '2013-08-26' then c.Value end) as [2013-08-26],
   max(case when t.DateCreated = '2013-08-27' then c.Value end) as [2013-08-27],
   max(case when t.DateCreated = '2013-08-28' then c.Value end) as [2013-08-28],
   max(case when t.DateCreated = '2013-08-29' then c.Value end) as [2013-08-29],
   max(case when t.DateCreated = '2013-08-30' then c.Value end) as [2013-08-30],
   max(case when t.DateCreated = '2013-08-31' then c.Value end) as [2013-08-31],
   max(case when t.DateCreated = '2013-09-01' then c.Value end) as [2013-09-01]
from test as t
   outer apply (
       select 'Rands', Rands union all
       select 'Units', Units union all
       select 'Average Price', [Average Price] union all
       select 'Success %', [Success %] union all
       select 'Unique Users', [Unique Users]
   ) as C(Name, Value)
group by c.Name

您可以为此创建动态 SQL，如下所示：

declare @stmt nvarchar(max)

select @stmt = isnull(@stmt + ',', '') + 
    'max(case when t.DateCreated = ''' + convert(nvarchar(8), t.DateCreated, 112) + ''' then c.Value end) as [' + convert(nvarchar(8), t.DateCreated, 112) + ']'
from test as t

select @stmt = '
   select
       c.Name, ' + @stmt + ' from test as t
   outer apply (
       select ''Rands'', Rands union all
       select ''Units'', Units union all
       select ''Average Price'', [Average Price] union all
       select ''Success %'', [Success %] union all
       select ''Unique Users'', [Unique Users]
   ) as C(Name, Value)
   group by c.Name'

exec sp_executesql @stmt = @stmt

Answer 2

我最终使用动态 sql 解决了这个问题，与标记的答案非常相似。如果没有动态 sql，我无法找到这样做的方法。日期必须按顺序排列，最后 7 天，他们还必须使用星期几的名称（我没有在问题中指定）。

我需要做的最大改变是将表变量更改为临时表。 这是因为动态 sql 语句在不同的上下文中执行，并且不知道您创建的任何变量。

最后，我在尝试使用 PIVOT 时完全偏离了轨道，而 APPLY 应该用于存在不止一种“类型”值的情况。

我在下面提供了我的解决方案，因为它可以帮助遇到类似问题的人：

CREATE TABLE #SummaryTable
(
    [DateCreated] DATE UNIQUE,
    [Rands] DECIMAL,
    [Units] INT,
    [Average Price] DECIMAL,
    [Success %] INT,
    [Unique Users] INT
);

--Code to fill table

declare @stmt nvarchar(max)

select @stmt = isnull(@stmt + ',', '') + 
    'max(case when t.DateCreated = ''' + convert(nvarchar(16), t.DateCreated, 126)
 + ''' then c.Value end) as [' + left(datename(dw, t.DateCreated),3) + ']'
from #SummaryTable as t

select @stmt = '
   select
       c.Name, ' + @stmt + ' from #SummaryTable as t
   outer apply (
       select ''Rands'', Rands union all
       select ''Units'', Units union all
       select ''Average Price'', [Average Price] union all
       select ''Success'', [Success %] union all
       select ''Unique Users'', [Unique Users]
   ) as C(Name, Value)
   group by c.Name'

exec(@stmt)