SQL Server查询以查找4个连续值的总和

问题描述

| 有人可以帮我找到四个连续值的总和，即最后四个值的总和。 喜欢：

VALUE   SUM
1   NULL
2   NULL
3   NULL
4   10
5   14
6   18
7   22
8   26
9   30
10  34
11  38
12  42
13  46
14  50
15  54
16  58
17  62
18  66
19  70
20  74
21  78
22  82
23  86
24  90
25  94
26  98
27  102
28  106
29  110
30  114
31  118
32  122
33  126
34  130
35  134
36  138
37  142
38  146

谢谢，     

解决方法

        

select sum(select top 4 Value from [table] order by Value Desc)

也许

select sum(value)
from [Table]
where Value >= (Max(Value) - 4)

我实际上还没有尝试过，而且目前也不能尝试，但是它们应该可以使您更加接近。     ,        快速尝试，获取您在问题中发布的结果（第1行，第3行不是NULL）。假设VALUE字段是唯一的且按升序排列：

-- Create test TABLE with 38 values in
DECLARE @T TABLE (Value INTEGER)
DECLARE @Counter INTEGER
SET @Counter = 1
WHILE (@Counter <= 38)
    BEGIN
        INSERT @T VALUES(@Counter)
        SET @Counter = @Counter + 1
    END

-- This gives the results   
SELECT t1.VALUE,x.Val
FROM @T t1
    OUTER APPLY(SELECT SUM(VALUE) FROM (SELECT TOP 4 VALUE FROM @T t2 WHERE t2.VALUE <= t1.VALUE ORDER BY t2.VALUE DESC) x) AS x(Val)
ORDER BY VALUE

至少，您应该看到我要走的方向。     ,        假设ID可以给您最后4行。

SELECT SUM([SUM])
FROM
    (
    SELECT TOP 4 [SUM] FROM myTable ORDER BY ID DESC
    ) foo

每次查询时，它将读取最后4行。 如果这是错误的（例如，您需要连续四行的总和），请提供示例输出     ,        如果您的“ 5”列是连续的，则可以执行以下操作

;WITH q (Value) AS (
    SELECT  1
    UNION ALL
    SELECT  q.Value + 1
    FROM    q
    WHERE   q.Value < 38
)

SELECT  q.Value,CASE WHEN q.Value >= 4 THEN q.Value * 4 - 6 ELSE NULL END
FROM    q       

否则你可能会使用这样的东西

;WITH q (Value) AS (
    SELECT  1
    UNION ALL
    SELECT  q.Value + 1
    FROM    q
    WHERE   q.Value < 38
),Sequential (ID,Value) AS (
    SELECT  ID = ROW_NUMBER() OVER (ORDER BY Value),Value
    FROM    q
)
SELECT  s1.Value,[SUM] = s1.Value + s2.Value + s3.Value + s4.Value
FROM    Sequential s1
        LEFT OUTER JOIN Sequential s2 ON s2.ID = s1.ID - 1
        LEFT OUTER JOIN Sequential s3 ON s3.ID = s2.ID - 1
        LEFT OUTER JOIN Sequential s4 ON s4.ID = s3.ID - 1

请注意，示例中的表ѭ8是实际表的存根。实际的陈述变成

;WITH Sequential (ID,Value
    FROM    YourTable
)
SELECT  s1.Value,[SUM] = s1.Value + s2.Value + s3.Value + s4.Value
FROM    Sequential s1
        LEFT OUTER JOIN Sequential s2 ON s2.ID = s1.ID - 1
        LEFT OUTER JOIN Sequential s3 ON s3.ID = s2.ID - 1
        LEFT OUTER JOIN Sequential s4 ON s4.ID = s3.ID - 1