如何通過總和來限制SQ​​L Server中的選擇？

Question

我可以通過SQL Server數據庫中的列的總和來限制行嗎？

例如：

Type | Time (in minutes) 
------------------------- 
A | 50 
B | 10 
C | 30 
D | 20 
E | 70 
... 

而且我想通過時間總和限制選擇。例如最多100分鐘。表格必須如下所示：

Type | Time (in minutes) 
------------------------- 
A | 50 
B | 10 
C | 30 

任何想法？謝謝。

Answer 1

DECLARE @T TABLE 
(
[Type] CHAR(1) PRIMARY KEY, 
[Time] INT 
) 
INSERT INTO @T 
SELECT 'A',50 UNION ALL 
SELECT 'B',10 UNION ALL 
SELECT 'C',30 UNION ALL 
SELECT 'D',20 UNION ALL 
SELECT 'E',70; 


WITH RecursiveCTE 
AS  (
     SELECT TOP 1 [Type], [Time], CAST([Time] AS BIGINT) AS Total 
     FROM @T 
     ORDER BY [Type] 
     UNION ALL 
     SELECT R.[Type], R.[Time], R.Total 
     FROM (
       SELECT T.*, 
         T.[Time] + Total AS Total, 
         rn = ROW_NUMBER() OVER (ORDER BY T.[Type]) 
       FROM @T T 
       JOIN RecursiveCTE R 
         ON R.[Type] < T.[Type] 
       ) R 
     WHERE R.rn = 1 AND Total <= 100 
     ) 
SELECT [Type], [Time], Total 
FROM RecursiveCTE 
OPTION (MAXRECURSION 0); 

或者，如果你的表是小

SELECT t1.[Type], 
     t1.[Time], 
     SUM(t2.[Time]) 
FROM @T t1 
JOIN @T t2 
ON t2.[Type] <= t1.[Type] 
GROUP BY t1.[Type],t1.[Time] 
HAVING SUM(t2.[Time]) <=100