我有一个以下格式的数据库:
ID TYPE SUBTYPE COUNT MONTH
1 A Z 1 7/1/2008
1 A Z 3 7/1/2008
2 B C 2 7/2/2008
1 A Z 3 7/2/2008是否可以使用SQL将其转换为以下格式:
ID A_Z B_C MONTH
1 4 0 7/1/2008
2 0 2 7/2/2008
1 0 3 7/2/2008因此,TYPE和SUBTYPE被连接到新的列中,并且COUNT在ID和MONTH匹配的地方求和。
任何建议都将不胜感激。这在SQL中是可能的,还是应该手动编程?
数据库为SQL Server 2005。
假设有100个TYPES和SUBTYPES,那么'A‘和'Z’不应该是硬编码的,而是动态生成的。
发布于 2008-10-01 21:18:38
SQL Server2005提供了一个非常有用的PIVOT和UNPIVOT运算符,它允许您使用PIVOT和一些代码生成/动态SQL使代码免维护
/*
CREATE TABLE [dbo].[stackoverflow_159456](
[ID] [int] NOT NULL,
[TYPE] [char](1) NOT NULL,
[SUBTYPE] [char](1) NOT NULL,
[COUNT] [int] NOT NULL,
[MONTH] [datetime] NOT NULL
) ON [PRIMARY]
*/
DECLARE @sql AS varchar(max)
DECLARE @pivot_list AS varchar(max) -- Leave NULL for COALESCE technique
DECLARE @select_list AS varchar(max) -- Leave NULL for COALESCE technique
SELECT @pivot_list = COALESCE(@pivot_list + ', ', '') + '[' + PIVOT_CODE + ']'
,@select_list = COALESCE(@select_list + ', ', '') + 'ISNULL([' + PIVOT_CODE + '], 0) AS [' + PIVOT_CODE + ']'
FROM (
SELECT DISTINCT [TYPE] + '_' + SUBTYPE AS PIVOT_CODE
FROM stackoverflow_159456
) AS PIVOT_CODES
SET @sql = '
;WITH p AS (
SELECT ID, [MONTH], [TYPE] + ''_'' + SUBTYPE AS PIVOT_CODE, SUM([COUNT]) AS [COUNT]
FROM stackoverflow_159456
GROUP BY ID, [MONTH], [TYPE] + ''_'' + SUBTYPE
)
SELECT ID, [MONTH], ' + @select_list + '
FROM p
PIVOT (
SUM([COUNT])
FOR PIVOT_CODE IN (
' + @pivot_list + '
)
) AS pvt
'
EXEC (@sql)发布于 2008-10-01 20:12:55
select id,
sum(case when type = 'A' and subtype = 'Z' then [count] else 0 end) as A_Z,
sum(case when type = 'B' and subtype = 'C' then [count] else 0 end) as B_C,
month
from tbl_why_would_u_do_this
group by id, month您更改需求的次数比我们的营销团队还多!如果你想让它是动态的,你需要依赖于一个存储过程。
https://stackoverflow.com/questions/159456
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