Linq to SQL中是否提供Unpivot(非枢轴)功能?如何? [英] Is Unpivot (Not Pivot) functionality available in Linq to SQL? How?
问题描述
我看过一些文章,这些文章可以为您带来关键的结果,但并非毫无疑问,需要知道是否有任何明确的方法可以实现?如果不是,那么任何解决方法都可以吗?
I have seen posts which would fetch you pivot results but not unpivot, Need to know if there is any clean way to achieve ? If not the any workaround would do as well ?
执行此操作以在Management Studio中查看未更改的结果
Execute this to see unpivot results in Management Studio
CREATE TABLE [dbo].[Payment](
[PaymentId] [int] NOT NULL,
[EmployeeId] [int] NOT NULL,
[RegularHours] [decimal](18, 0) NULL,
[OvertimeHOurs] [decimal](18, 0) NULL
) ON [PRIMARY]
go
insert into payment values (1, 1, 40, 10)
insert into payment values (1, 2, 20, 0)
go
select * from payment
select * from payment unpivot ([hours] for [paytype] in ([RegularHours], [OvertimeHOurs]))a
第一个Select语句的输出
The output for first Select statement
PaymentId EmployeeId RegularHours OvertimeHOurs
----------- ----------- ---------------------------------------
1 1 40 10
1 2 20 0
(2 row(s) affected)
第二个Select语句&的输出这就是我正在寻找的
The output for second Select statement & this is what i am looking for
PaymentId EmployeeId hours paytype
----------- ----------- -----------------------------------------------------
1 1 40 RegularHours
1 1 10 OvertimeHOurs
1 2 20 RegularHours
1 2 0 OvertimeHOurs
(4 row(s) affected)
推荐答案
好吧,我看不到将其转换为SQL的方法,以下是我想出的方法,但这都是执行的托管代码.
Ok, I cant see a way you can do it where it is translated into SQL, below is what I have come up with but this is all performed managed code.
或者...您可以简单地在SQL中创建视图.
Or... you can simply create a view in SQL.
var payments = Payments.Select (p => new {
OvertimeHOurs = new {
p.PaymentId,
p.EmployeeId,
Hours = p.OvertimeHOurs,
PayType = "OvertimeHOurs"
},
RegularHours = new {
p.PaymentId,
p.EmployeeId,
Hours = p.RegularHours,
PayType = "RegularHours"
}
}
);
var result = payments.Select(a => a.OvertimeHOurs).Union(payments.Select (p => p.RegularHours));
result.Dump(); // LINQPad Method
生成的SQL是
-- Region Parameters
DECLARE @p0 NVarChar(1000) = 'OvertimeHOurs'
DECLARE @p1 NVarChar(1000) = 'RegularHours'
-- EndRegion
SELECT [t4].[PaymentId], [t4].[EmployeeId], [t4].[OvertimeHOurs] AS [Hours], [t4].[value] AS [PayType]
FROM (
SELECT [t1].[PaymentId], [t1].[EmployeeId], [t1].[OvertimeHOurs], [t1].[value]
FROM (
SELECT [t0].[PaymentId], [t0].[EmployeeId], [t0].[OvertimeHOurs], @p0 AS [value]
FROM [payment] AS [t0]
) AS [t1]
UNION
SELECT [t3].[PaymentId], [t3].[EmployeeId], [t3].[RegularHours], [t3].[value]
FROM (
SELECT [t2].[PaymentId], [t2].[EmployeeId], [t2].[RegularHours], @p1 AS [value]
FROM [payment] AS [t2]
) AS [t3]
) AS [t4]
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