Question

我有一个名为work_type的表，数据如下：

Desc               L_type      Ch_ID      Mod_Date
Std Process        11000       53901      2012-02-25 19:28:51.000
Not Req            16000       53901      2012-02-26 20:44:47.000
max sess           19000       53901      2012-02-25 19:44:05.000
max sess regist    19000       53901      2012-02-25 19:46:05.000

当L_type有多行时（对于上述数据中的Ex 19000），则需要基于Mod_Date的最新行

我希望输出如下：

Te_pl      In_pl               Vn_pl         Ch_ID
Not Req    max sess regist     Std process   53901

我写了这样的查询，但这不是我想要的：

Select Case when L_type = 11000 then Desc end as Vn_pl,
Case when L_type = 16000 then Desc end as Te_pl,
Case when L_type = 11000 then Desc end as In_pl,
Ch_ID
from dbo.Work_type

Answer 1

如果你只想要需要三列，那么这应该可以解决问题 - 如果没有，那么我会建议寻找动态旋转：

;WITH data AS
(
SELECT 
[desc]
,l_type
,ch_id
,mod_date
,DENSE_RANK() OVER (PARTITION BY ch_id,l_type ORDER BY mod_date DESC) AS row
FROM dbo.Work_type
)
,data2 AS
(
SELECT * 
,row_number() OVER (PARTITION BY ch_id ORDER BY mod_date DESC) AS row1
from data
WHERE row = 1
)
SELECT 
MAX(Case when row1 = 1 THEN [desc] END) AS te_pl
,MAX(Case when row1 = 2 THEN [desc] END) AS in_pl
,MAX(Case when row1 = 3 THEN [desc] END) AS vn_pl
,CH_id
FROM data2
GROUP BY CH_ID

Answer 2

以下是一种基于XML的转换整个表的方法：here

Answer 3

您是否尝试透视数据？

查看PIVOT关键字。

多行到列中

3 个答案: