值X到Y的SQL增量字段

我试图在@start和@end两个变量之间，通过@increment来获取一个字段，在@end处重置，然后在@start处重新开始，并继续表中的所有行

如果

那么我要找的是：

1 .06
2 .08
3 .10
4 .06
5 .08
6 .10

---

我尝试过使用带模的Row_Number（），但在第一次重置后就不起作用了

您可以使用递归CTE：

with cte as (
      select 1 as n, cast(@start as decimal(10, 2)) as val
      union all
      select n + 1, cast(val + @increment as decimal(10, 2))
      from cte
      where val + @increment <= @end
     )
select * 
from cte cross join
     t;

子查询计算序列号和grp的大小。外部查询对行号进行分区，然后进行算术运算

基本上相同的想法可以做到如下：

select t.*,
       (@start + @increment * (row_number() over (order by id) - 1) % cast(1 + round((@end - @start) / @increment, 0) as int))
from t;

---

但是这个算法有点难以理解。

我想您正在寻找一种解决方案来更新表中的字段。您可以使用一个变量来执行此操作，如下所示

您需要将更新间隔写入

WHERE

条件

DECLARE @Tbl TABLE (Id INT, TempColumn FLOAT)

INSERT INTO @Tbl (Id)
VALUES
(1),(2),(3),(4)    

DECLARE @Inc FLOAT = 0 

UPDATE @Tbl
SET TempColumn = @Inc,
    @Inc += 0.2    

SELECT * FROM @Tbl

结果:

Id          TempColumn
----------- --------------
1           0,2
2           0,4
3           0,6
4           0,8

---

使用递归cte根据需要生成数字（表中的行数）。然后使用表达式在每3行之后重置序列

declare @start decimal(10,2)=0.06;
declare @end decimal(10,2)=0.1;
declare @increment decimal(10,2)=0.02;

with numbers(rnum) as (select 1
                       union all
                       select rnum+1
                       from numbers where rnum<100 ) 
select (rnum-1)%3*@increment+@start as col
from numbers

---

我经常使用表值函数来创建动态范围。通常比递归cte更快，并且具有参数驱动的附加好处，并且容易合并到子查询、交叉应用甚至交叉连接中，如下图所示：

示例

Declare @start float     = .06 
Declare @end float       = .10
Declare @increment float = .02

Declare @groups  int     = 3    

Select ID    = Row_Number() over (Order by A.RetSeq)
      ,Value = B.RetVal
 From  [dbo].[udf-Range-Number](1,@groups,1) A
 Cross Apply [dbo].[udf-Range-Number](@start,@end,@increment) B
 Order By 1,2

返回

ID  Value
1   0.06
2   0.08
3   0.10
4   0.06
5   0.08
6   0.10
7   0.06
8   0.08
9   0.10

有兴趣的UDF

CREATE FUNCTION [dbo].[udf-Range-Number] (@R1 money,@R2 money,@Incr money)
Returns Table
Return (
    with cte0(M) As (Select cast((@R2-@R1)/@Incr as int)),
         cte1(N) As (Select 1 From (Values(1),(1),(1),(1),(1),(1),(1),(1),(1),(1)) N(N)),
         cte2(N) As (Select Top (Select M from cte0) Row_Number() over (Order By (Select NULL)) From cte1 a,cte1 b,cte1 c,cte1 d,cte1 e,cte1 f,cte1 g,cte1 h )

    Select RetSeq=1,RetVal=@R1 Union All Select N+1,(N*@Incr)+@R1
    From   cte2   
)
-- Max 100 million observations 
-- Select * from [dbo].[udf-Range-Number](0,4,0.25)

---

您必须生成多少这样的行？请使用行发布您尝试的代码_number@vkp行数取决于表中可变的其他字段。它基本上只需要继续，直到像Row_Number（）那样结束。。这不会生成超过3行。

Declare @start float     = .06 
Declare @end float       = .10
Declare @increment float = .02

Declare @groups  int     = 3    

Select ID    = Row_Number() over (Order by A.RetSeq)
      ,Value = B.RetVal
 From  [dbo].[udf-Range-Number](1,@groups,1) A
 Cross Apply [dbo].[udf-Range-Number](@start,@end,@increment) B
 Order By 1,2

ID  Value
1   0.06
2   0.08
3   0.10
4   0.06
5   0.08
6   0.10
7   0.06
8   0.08
9   0.10

CREATE FUNCTION [dbo].[udf-Range-Number] (@R1 money,@R2 money,@Incr money)
Returns Table
Return (
    with cte0(M) As (Select cast((@R2-@R1)/@Incr as int)),
         cte1(N) As (Select 1 From (Values(1),(1),(1),(1),(1),(1),(1),(1),(1),(1)) N(N)),
         cte2(N) As (Select Top (Select M from cte0) Row_Number() over (Order By (Select NULL)) From cte1 a,cte1 b,cte1 c,cte1 d,cte1 e,cte1 f,cte1 g,cte1 h )

    Select RetSeq=1,RetVal=@R1 Union All Select N+1,(N*@Incr)+@R1
    From   cte2   
)
-- Max 100 million observations 
-- Select * from [dbo].[udf-Range-Number](0,4,0.25)