Sql 按列分组数据
可能重复:Sql 按列分组数据,sql,sql-server,sql-server-2008,tsql,Sql,Sql Server,Sql Server 2008,Tsql,可能重复: 我有一个名为Col_values的表,Col_ID是一个标识字段,数据如下所示: Val_ID Col_ID Value 76951792 3 Closed 76951791 3 Closed 76951790 25 Open 76951789 25 Closed 76951792 1 US 76951791
我有一个名为Col_values的表,Col_ID是一个标识字段,数据如下所示:
Val_ID Col_ID Value
76951792 3 Closed
76951791 3 Closed
76951790 25 Open
76951789 25 Closed
76951792 1 US
76951791 1 Canada
Col_ID Col_Name D_ID
3 Status 1
25 Status 2
1 Country 1
另一个表叫做Et_Col,数据如下所示:
Val_ID Col_ID Value
76951792 3 Closed
76951791 3 Closed
76951790 25 Open
76951789 25 Closed
76951792 1 US
76951791 1 Canada
Col_ID Col_Name D_ID
3 Status 1
25 Status 2
1 Country 1
我希望输出为:
Val_ID Status Country
76951792 Closed US
76951791 Closed Canada
76951790 Open Null
76951789 Closed Null
Val_ID Status Status Country
76951792 Closed Null US
76951791 Closed Null Canada
76951789 Null Closed Null
76951790 Null Open Null
因此,我编写了一个游标来获取输出,游标返回如下语句:
Select val_ID
,max(case when Col_ID = 3 then Value end) as Status
,max(case when Col_ID = 25 then Value end) as Status
,max(CASE WHEN Col_ID = 1 THEN VALUE END ) AS Country
From Col_values
Group by Val_ID
这使我的输出为:
Val_ID Status Country
76951792 Closed US
76951791 Closed Canada
76951790 Open Null
76951789 Closed Null
Val_ID Status Status Country
76951792 Closed Null US
76951791 Closed Null Canada
76951789 Null Closed Null
76951790 Null Open Null
我怎样才能解决这个问题
select val_id, value as Status
from col_values
这就是你想要的产出。为什么您认为您需要对数据进行分组才能获得这些数据???应该可以更改光标,使其生成如下sql:
select
val_id
,max(case when Col_name = 'Status' then Value end) as Status
,max(case when Col_name = 'Country' then Value end) as Country
from
col_values v
join ET_Col c on v.col_id=c.col_id
group by val_id
不同的是,您使用列名称而不是列id在列之间拆分,因此折叠的列名将合并。请参阅我编辑的问题。我在表格中加入了更多的样本数据。因此,您可以看到我为什么要对dataPivot进行分组,这是您要寻找的关键词:非常类似于您知道术语规范化吗?这可以通过动态pivot表来完成:我刚刚给了您一些示例数据,但大约有100个Col_ID。所以我不能写SQl,这就是为什么我写游标,它给我上面写的select语句,我已经更新了。我认为,基于您已经能够生成的内容,您将能够相当容易地生成上面的sql。