如何使用 WHILE LOOP 将值添加到有条件的列表中，SQL Server 2008答案

【问题标题】：How to use WHILE LOOP to add value to list with condition, SQL Server 2008如何使用 WHILE LOOP 将值添加到有条件的列表中，SQL Server 2008
【发布时间】：2015-07-08 07:45:47
【问题描述】：

我有一个循环查询，场景如下：

orderqty = 每个循环增加值 1
runningstock = 每个循环减少 1 个值
allocateqty = orderqty > 0 且 runningstock > 0 然后 1 else 的情况 0
循环直到 runningstock=0 或 total allocation=stockqty

查询：

DECLARE @RESULT TABLE (priority int,partcode nvarchar(50),orderqty int, runningstock int, allocateqty int)
DECLARE @ORDER TABLE(priority int,partcode nvarchar(50),orderqty int)
DECLARE @STOCK TABLE(partcode nvarchar(50),stockqty int)

INSERT INTO @ORDER (priority,partcode,orderqty)
VALUES(1,'A',2),
    (2,'A',10),
    (3,'A',3),
    (4,'A',8);

INSERT INTO @STOCK(partcode,stockqty)
VALUES('A',20);

DECLARE @allocateqty int=1
DECLARE @runningstock int=(SELECT stockqty FROM @stock)

WHILE @runningstock>=0
BEGIN
    INSERT INTO @RESULT(priority,partcode,orderqty,runningstock,allocateqty)
    SELECT priority,
           partcode, 
           orderqty,
           @runningstock,
           CASE WHEN @runningstock > 0 AND orderqty > 0 THEN 1 ELSE 0 END
    FROM @order
    SET @runningstock -=1
 END

SELECT * FROM @Result

GO

结果：

priority    partcode    orderqty    runningstock    allocateqty
1   A   2   20  1
2   A   10  20  1
3   A   3   20  1
4   A   8   20  1
1   A   2   19  1
2   A   10  19  1
3   A   3   19  1
4   A   8   19  1
1   A   2   18  1
2   A   10  18  1
3   A   3   18  1
4   A   8   18  1
1   A   2   17  1
2   A   10  17  1
3   A   3   17  1
4   A   8   17  1
1   A   2   16  1
2   A   10  16  1
3   A   3   16  1
4   A   8   16  1
1   A   2   15  1
2   A   10  15  1
3   A   3   15  1
4   A   8   15  1
1   A   2   14  1
2   A   10  14  1
3   A   3   14  1
4   A   8   14  1
1   A   2   13  1
2   A   10  13  1
3   A   3   13  1
4   A   8   13  1
1   A   2   12  1
2   A   10  12  1
3   A   3   12  1
4   A   8   12  1
1   A   2   11  1
2   A   10  11  1
3   A   3   11  1
4   A   8   11  1
1   A   2   10  1
2   A   10  10  1
3   A   3   10  1
4   A   8   10  1
1   A   2   9   1
2   A   10  9   1
3   A   3   9   1
4   A   8   9   1
1   A   2   8   1
2   A   10  8   1
3   A   3   8   1
4   A   8   8   1
1   A   2   7   1
2   A   10  7   1
3   A   3   7   1
4   A   8   7   1
1   A   2   6   1
2   A   10  6   1
3   A   3   6   1
4   A   8   6   1
1   A   2   5   1
2   A   10  5   1
3   A   3   5   1
4   A   8   5   1
1   A   2   4   1
2   A   10  4   1
3   A   3   4   1
4   A   8   4   1
1   A   2   3   1
2   A   10  3   1
3   A   3   3   1
4   A   8   3   1
1   A   2   2   1
2   A   10  2   1
3   A   3   2   1
4   A   8   2   1
1   A   2   1   1
2   A   10  1   1
3   A   3   1   1
4   A   8   1   1
1   A   2   0   0
2   A   10  0   0
3   A   3   0   0
4   A   8   0   0

正确的应该是这样的：

priority    partcode    orderqty    runningstock    allocateqty
1   A   2   20  1
2   A   10  19  1
3   A   3   18  1
4   A   8   17  1
1   A   1   16  1
2   A   9   15  1
3   A   2   14  1
4   A   7   13  1
1   A   0   12  0
2   A   8   12  1
3   A   1   11  1
4   A   6   10  1
1   A   0   9   0
2   A   7   9   1
3   A   0   8   0
4   A   5   8   1
1   A   0   7   0
2   A   6   7   1
3   A   0   6   0
4   A   4   6   1
1   A   0   5   0
2   A   5   5   1
3   A   0   4   0
4   A   3   4   1
1   A   0   3   0
2   A   4   3   1
3   A   0   2   0
4   A   2   2   1
1   A   0   1   0
2   A   3   1   1
3   A   0   0   0

【问题讨论】：

标签： sql sql-server while-loop

【解决方案1】：

您还可以遍历您的优先级并确保相应地更新 orderqty。我会做这样的事情：

DECLARE @allocatedqty int = 0
DECLARE @allocateqty int = 1
DECLARE @runningstock int = (SELECT stockqty FROM @stock)

WHILE @runningstock>=0
BEGIN
    DECLARE @priority int
    SELECT TOP 1 @priority = priority FROM @order ORDER BY priority ASC

    WHILE @priority <= (SELECT MAX(priority) FROM @order)
    BEGIN
        DECLARE @orderqty int
        SELECT @orderqty = orderqty - @allocatedqty FROM @order WHERE priority = @priority
        SELECT @allocateqty = CASE WHEN @runningstock > 0 AND @orderqty > 0 THEN 1 ELSE 0 END

        INSERT INTO @RESULT(priority,partcode,orderqty,runningstock,allocateqty)
        SELECT @priority,
               partcode, 
               CASE WHEN @orderqty >= 0 THEN @orderqty ELSE 0 END AS orderqty,
               @runningstock,
               @allocateqty
        FROM @order 
        WHERE priority = @priority

        SET @priority += 1      
        SET @runningstock = @runningstock - @allocateqty
    END
    SET @allocatedqty += 1

    IF (@runningstock <= 0) BREAK 
 END

SELECT * FROM @Result

GO

【讨论】：

你让我开心:)，这与一个部分代码完美配合，以防我有多个部分代码（A、B、C..）它错误：子查询返回超过 1 个值。当子查询跟随 =、!=、、>= 或子查询用作表达式时，这是不允许的。

【解决方案2】：

应尽可能避免在 sql 中循环。这将为您提供所描述的结果（除非您的倒计时中有 2 个错误）：

DECLARE @ORDER TABLE(priority int,partcode nvarchar(50),orderqty int)

INSERT INTO @ORDER (priority,partcode,orderqty)
VALUES(1,'A',2),
    (2,'A',10),
    (3,'A',3),
    (4,'A',8);

DECLARE @runningstock INT = 20
;WITH CTE AS
(
  SELECT 
    priority, 
    partcode, 
    orderqty, 
    @runningstock + 1 - priority runningstock, 
    sign(orderqty) allocateqty
  FROM @ORDER
  UNION ALL
  SELECT 
    priority, 
    partcode, 
    orderqty - sign(orderqty), 
    runningstock - 4, 
    sign(orderqty - sign(orderqty))
  FROM CTE
  WHERE runningstock > 3
)
SELECT 
  priority, partcode, orderqty, runningstock, allocateqty
FROM CTE
ORDER BY runningstock desc, priority

结果：

priority     partcode     orderqty     runningstock  allocateqty
1            A            2            20            1
2            A            10           19            1
3            A            3            18            1
4            A            8            17            1
1            A            1            16            1
2            A            9            15            1
3            A            2            14            1
4            A            7            13            1
1            A            0            12            0
2            A            8            11            1
3            A            1            10            1
4            A            6            9             1
1            A            0            8             0
2            A            7            7             1
3            A            0            6             0
4            A            5            5             1
1            A            0            4             0
2            A            6            3             1
3            A            0            2             0
4            A            4            1             1
1            A            0            0             0

【讨论】：

@t-clause.dk totalallocatedqty=15 其中运行库存=20 和 orderqty=23，如果 stockqty

【解决方案3】：

不是最好的方法，但你会得到预期的结果

DECLARE @RESULT TABLE (priority int,partcode nvarchar(50),orderqty int, runningstock int, allocateqty int)
DECLARE @ORDER TABLE(priority int,partcode nvarchar(50),orderqty int)
DECLARE @STOCK TABLE(partcode nvarchar(50),stockqty int)

INSERT INTO @ORDER (priority,partcode,orderqty)
VALUES(1,'A',2),
      (2,'A',10),
      (3,'A',3),
      (4,'A',8);

INSERT INTO @STOCK(partcode,stockqty)
VALUES ('A',20);

DECLARE @allocateqty int=1
DECLARE @runningstock int=(SELECT stockqty FROM @stock)

DECLARE @OutputTbl TABLE (orderqty INT)

WHILE @runningstock>0
BEGIN
    INSERT INTO @RESULT(priority,partcode,orderqty,runningstock,allocateqty)
    OUTPUT inserted.allocateqty INTO @OutputTbl
    SELECT priority,
           partcode, 
           orderqty,
           @runningstock,
           CASE WHEN @runningstock > 0 AND orderqty > 0 THEN 1 ELSE 0 END
    FROM @order
    WHERE priority = 1
    
    SELECT @runningstock -=  SUM(orderqty) FROM @OutputTbl
    UPDATE @order SET orderqty -= (SELECT SUM(orderqty) FROM @OutputTbl) WHERE priority = 1 
    DELETE FROM @OutputTbl

    INSERT INTO @RESULT(priority,partcode,orderqty,runningstock,allocateqty)
    OUTPUT inserted.allocateqty INTO @OutputTbl
    SELECT priority,
           partcode, 
           orderqty,
           @runningstock,
           CASE WHEN @runningstock > 0 AND orderqty > 0 THEN 1 ELSE 0 END
    FROM @order
    WHERE priority = 2
    
    SELECT @runningstock -=  SUM(orderqty) FROM @OutputTbl
    UPDATE @order SET orderqty -= (SELECT SUM(orderqty) FROM @OutputTbl) WHERE priority = 2
    DELETE FROM @OutputTbl

    INSERT INTO @RESULT(priority,partcode,orderqty,runningstock,allocateqty)
    OUTPUT inserted.allocateqty INTO @OutputTbl
    SELECT priority,
           partcode, 
           orderqty,
           @runningstock,
           CASE WHEN @runningstock > 0 AND orderqty > 0 THEN 1 ELSE 0 END
    FROM @order
    WHERE priority = 3
    
    SELECT @runningstock -=  SUM(orderqty) FROM @OutputTbl
    UPDATE @order SET orderqty -= (SELECT SUM(orderqty) FROM @OutputTbl) WHERE priority = 3
    DELETE FROM @OutputTbl
    

    INSERT INTO @RESULT(priority,partcode,orderqty,runningstock,allocateqty)
    OUTPUT inserted.allocateqty INTO @OutputTbl
    SELECT priority,
           partcode, 
           orderqty,
           @runningstock,
           CASE WHEN @runningstock > 0 AND orderqty > 0 THEN 1 ELSE 0 END
    FROM @order
    WHERE priority = 4
    
    SELECT @runningstock -=  SUM(orderqty) FROM @OutputTbl
    UPDATE @order SET orderqty -= (SELECT SUM(orderqty) FROM @OutputTbl) WHERE priority = 4
    DELETE FROM @OutputTbl

    print @runningstock
 END

SELECT * FROM @Result

GO

如您所见，我将优先级分为 4 个步骤，在每个步骤中我都会降低跑步机

SELECT @runningstock -=  SUM(orderqty) FROM @OutputTbl

订单数量

UPDATE @order SET orderqty -= (SELECT SUM(orderqty) FROM @OutputTbl) WHERE priority = 1

基于分配数量

OUTPUT inserted.allocateqty INTO @OutputTbl

【讨论】：

谢谢。反正我的实际数据是超过 10,00 的优先级。有没有办法让它更容易和自动？我的意思是在这里您需要手动更新订单并设置 where 子句。

【解决方案4】：

WHILE @runningstock>=0
BEGIN
    INSERT INTO @RESULT(priority,partcode,orderqty,runningstock,allocateqty)
    SELECT priority,
           partcode, 
           orderqty,
           @runningstock,
           CASE WHEN @runningstock > 0 AND orderqty > 0 THEN 1 ELSE 0 END
    FROM @ORDER
    
    SET @runningstock =@runningstock-1
 END

【讨论】：

SET @runningstock -=1和@runningstock =@runningstock-1没有区别