2

我有一张这样的桌子...

LEVEL        Action         Date             User
--------------------------------------------------
1            Approve        01/01/2013       User1
2            Approve        02/01/2013       User2
3            Rejected       03/01/2013       User3
1            Approve        04/01/2013       User1
2            Approve        05/01/2013       User2
3            Approve        06/01/2013       User3
.                .              .              .
.                .              .              .
.                .              .              .

而我想要这个...

这可以使用 PIVOT 吗?

LEVEL1 - User 1           LEVEL2 - User 2                  LEVEL3 - User 3
---------------------------------------------------------------------------
01/01/2013 - Approve      02/01/2013 - Approve             03/01/2013 - Rejected
04/01/2013 - Approve      05/01/2013 - Approve             06/01/2013 - Approve
         .                        .                                .
         .                        .                                .

注意:级别数是动态的。例如,完全批准一个项目可以是 5 个级别、6 个级别等。所以数据透视表中的列数是动态的。

4

1 回答 1

7

是的,这可以使用PIVOT函数来完成,我首先建议查看查询的硬编码版本,以便在移动到查询的动态版本之前查看查询是如何编写的。

静态版本将类似于以下内容:

select [Level1 - User1], [Level2 - User2], [Level3 - User3]
from
(
  select 'Level'+cast(level as varchar(1)) + ' - '+ [user] col, 
    convert(varchar(10), date, 101) +' - '+ action value,
    row_number() over(partition by level order by [user], date) rn
  from yt
) d
pivot
(
  max(value)
  for col in ([Level1 - User1], [Level2 - User2], [Level3 - User3])
) piv;

请参阅SQL Fiddle with Demo。您会注意到leveluser列被连接以创建新列,并且dateaction被连接以创建每列的值。我还添加了row_number()一个为每一行创建一个唯一值,当您在 PIVOT 中应用聚合函数时,这将很重要。如果你不使用它,那么你将只得到一行。

由于您现在有一个工作版本,因此可以轻松地将其转换为动态版本:

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

select @cols = STUFF((SELECT distinct ',' + QUOTENAME('Level'+cast(level as varchar(1)) + ' - '+ [user]) 
                    from yt
            FOR XML PATH(''), TYPE
            ).value('.', 'NVARCHAR(MAX)') 
        ,1,1,'')

set @query = 'SELECT ' + @cols + ' from 
             (
                select ''Level''+cast(level as varchar(1)) + '' - ''+ [user] col, 
                  convert(varchar(10), date, 101) +'' - ''+ action value,
                  row_number() over(partition by level order by [user], date) rn
                from yt
            ) x
            pivot 
            (
                max(value)
                for col in (' + @cols + ')
            ) p '

execute(@query);

请参阅SQL Fiddle with Demo。两者的结果是:

|       LEVEL1 - USER1 |       LEVEL2 - USER2 |        LEVEL3 - USER3 |
-----------------------------------------------------------------------
| 01/01/2013 - Approve | 02/01/2013 - Approve | 03/01/2013 - Rejected |
| 04/01/2013 - Approve | 05/01/2013 - Approve |  06/01/2013 - Approve |
于 2013-05-07T11:28:13.897 回答