我怎么能替换T-SQL游标？
我想问你如何替换我插入存储过程的游标。
实际上，我们发现光标是管理我的场景的唯一出路，但正如我所知，这不是最佳做法。
这是我的场景：我必须逐行递归计算股票，并根据前一行计算的内容设置季节。
我可以设置转移类型为“购买”的季节。其他转移应通过T-SQL查询设置正确的季节。
我应该计算季节的表有以下模板和假数据，但它们反映了真实情况：
将“FlgSeason”设置为null的行计算如下：按升序，光标从第3行开始，返回前一行并计算每个季节的库存量，然后更新列季节与最低季节有库存。
这是我使用的代码：
CREATE TABLE [dbo].[transfers]
(
[rowId] [int] NULL,
[area] [int] NULL,
[store] [int] NULL,
[item] [int] NULL,
[date] [date] NULL,
[type] [nvarchar](50) NULL,
[qty] [int] NULL,
[season] [nvarchar](50) NULL,
[FlagSeason] [int] NULL
) ON [PRIMARY]
INSERT INTO [dbo].[transfers]
([rowId]
,[area]
,[store]
,[item]
,[date]
,[type]
,[qty]
,[season]
,[FlagSeason])
VALUES (1,1,20,300,'2015-01-01','Purchase',3,'2015-FallWinter',1)
, (2,1,20,300,'2015-01-01','Purchase',4,'2016-SpringSummer',1)
, (3,1,20,300,'2015-01-01','Sales',-1,null,null)
, (4,1,20,300,'2015-01-01','Sales',-2,null,null)
, (5,1,20,300,'2015-01-01','Sales',-1,null,null)
, (6,1,20,300,'2015-01-01','Sales',-1,null,null)
, (7,1,20,300,'2015-01-01','Purchase',4,'2016-FallWinter',1)
, (8,1,20,300,'2015-01-01','Sales',-1,null,null)
DECLARE @RowId as int
DECLARE db_cursor CURSOR FOR
Select RowID
from Transfers
where [FlagSeason] is null
order by RowID
OPEN db_cursor
FETCH NEXT FROM db_cursor INTO @RowId
WHILE @@FETCH_STATUS = 0
BEGIN
Update Transfers
set Season = (Select min (Season) as Season
from (
Select
Season
, SUM(QTY) as Qty
from Transfers
where RowID < @RowId
and [FlagSeason] = 1
group by Season
having Sum(QTY) > 0
)S
where s.QTY >= 0
)
, [FlagSeason] = 1
where rowId = @RowId
FETCH NEXT FROM db_cursor INTO @RowId
end
在这种情况下，查询将提取：
- 2015年第五季的FW
- 4 for 2016 SS。
比更新声明将设定2015-fw（两个赛季的分数与数量相比）。
然后courson前进第4行，并再次运行查询以提取更新的库存，考虑第3行的计算。所以结果应该是
- QTY 2 for 2015 FW
- 2016年第4期SS
然后更新将设置2015 FW。 等等。
最终输出应该是这样的：
实际上，唯一的出路是实现光标，现在扫描和更新大约250万行需要30/40分钟。有没有人知道一个解决方案而不重复使用游标？
提前致谢！
2 个答案:
答案 0 :(得分：1)
已更新为在2008年投放
IF OBJECT_ID('tempdb..#transfer') IS NOT NULL
DROP TABLE #transfer;
GO
CREATE TABLE #transfer (
RowID INT IDENTITY(1, 1) PRIMARY KEY NOT NULL,
Area INT,
Store INT,
Item INT,
Date DATE,
Type VARCHAR(50),
Qty INT,
Season VARCHAR(50),
FlagSeason INT
);
INSERT INTO #transfer ( Area,
Store,
Item,
Date,
Type,
Qty,
Season,
FlagSeason
)
VALUES (1, 20, 300, '20150101', 'Purchase', 3, '2015-SpringSummer', 1),
(1, 20, 300, '20150601', 'Purchase', 4, '2016-SpringSummer', 1),
(1, 20, 300, '20150701', 'Sales', -1, NULL, NULL),
(1, 20, 300, '20150721', 'Sales', -2, NULL, NULL),
(1, 20, 300, '20150901', 'Sales', -1, NULL, NULL),
(1, 20, 300, '20160101', 'Sales', -1, NULL, NULL),
(1, 20, 300, '20170101', 'Purchase', 4, '2017-SpringSummer', 1),
(1, 20, 300, '20170125', 'Sales', -1, NULL, NULL),
(1, 20, 300, '20170201', 'Sales', -1, NULL, NULL),
(1, 20, 300, '20170225', 'Sales', -1, NULL, NULL),
(1, 21, 301, '20150801', 'Purchase', 4, '2017-SpringSummer', 1),
(1, 21, 301, '20150901', 'Sales', -1, NULL, NULL),
(1, 21, 301, '20151221', 'Sales', -2, NULL, NULL),
(1, 21, 302, '20150801', 'Purchase', 1, '2016-SpringSummer', 1),
(1, 21, 302, '20150901', 'Purchase', 1, '2017-SpringSummer', 1),
(1, 21, 302, '20151101', 'Sales', -1, NULL, NULL),
(1, 21, 302, '20151221', 'Sales', -1, NULL, NULL),
(1, 20, 302, '20150801', 'Purchase', 1, '2016-SpringSummer', 1),
(1, 20, 302, '20150901', 'Purchase', 1, '2017-SpringSummer', 1),
(1, 20, 302, '20151101', 'Sales', -1, NULL, NULL),
(1, 20, 302, '20151221', 'Sales', -1, NULL, NULL);
WITH Purchases
AS (SELECT t1.RowID,
t1.Area,
t1.Store,
t1.Item,
t1.Date,
t1.Type,
t1.Qty,
t1.Season,
RunningInventory = ( SELECT SUM(t2.Qty)
FROM #transfer AS t2
WHERE t1.Type = t2.Type
AND t1.Area = t2.Area
AND t1.Store = t2.Store
AND t1.Item = t2.Item
AND t2.Date <= t1.Date
)
FROM #transfer AS t1
WHERE t1.Type = 'Purchase'
),
Sales
AS (SELECT t1.RowID,
t1.Area,
t1.Store,
t1.Item,
t1.Date,
t1.Type,
t1.Qty,
t1.Season,
RunningSales = ( SELECT SUM(ABS(t2.Qty))
FROM #transfer AS t2
WHERE t1.Type = t2.Type
AND t1.Area = t2.Area
AND t1.Store = t2.Store
AND t1.Item = t2.Item
AND t2.Date <= t1.Date
)
FROM #transfer AS t1
WHERE t1.Type = 'Sales'
)
SELECT Sales.RowID,
Sales.Area,
Sales.Store,
Sales.Item,
Sales.Date,
Sales.Type,
Sales.Qty,
Season = ( SELECT TOP 1
Purchases.Season
FROM Purchases
WHERE Purchases.Area = Sales.Area
AND Purchases.Store = Sales.Store
AND Purchases.Item = Sales.Item
AND Purchases.RunningInventory >= Sales.RunningSales
ORDER BY Purchases.Date, Purchases.Season
)
FROM Sales
UNION ALL
SELECT Purchases.RowID ,
Purchases.Area ,
Purchases.Store ,
Purchases.Item ,
Purchases.Date ,
Purchases.Type ,
Purchases.Qty ,
Purchases.Season
FROM Purchases
ORDER BY Sales.Area, Sales.Store, item, Sales.Date
*以下原始答案**
我不明白flagseason专栏的目的，所以我没有把它包括在内。从本质上讲，这会计算购买和销售的运行总和，然后查找每个销售交易至少具有sales_to_date流出量的purchase_to_date库存的季节。
IF OBJECT_ID('tempdb..#transfer') IS NOT NULL
DROP TABLE #transfer;
GO
CREATE TABLE #transfer (
RowID INT IDENTITY(1, 1) PRIMARY KEY NOT NULL,
Area INT,
Store INT,
Item INT,
Date DATE,
Type VARCHAR(50),
Qty INT,
Season VARCHAR(50),
FlagSeason INT
);
INSERT INTO #transfer ( Area,
Store,
Item,
Date,
Type,
Qty,
Season,
FlagSeason
)
VALUES (1, 20, 300, '20150101', 'Purchase', 3, '2015-FallWinter', 1),
(1, 20, 300, '20150601', 'Purchase', 4, '2016-SpringSummer', 1),
(1, 20, 300, '20150701', 'Sales', -1, NULL, NULL),
(1, 20, 300, '20150721', 'Sales', -2, NULL, NULL),
(1, 20, 300, '20150901', 'Sales', -1, NULL, NULL),
(1, 20, 300, '20160101', 'Sales', -1, NULL, NULL),
(1, 20, 300, '20170101', 'Purchase', 4, '2016-FallWinter', 1),
(1, 20, 300, '20170201', 'Sales', -1, NULL, NULL);
WITH Inventory
AS (SELECT *,
PurchaseToDate = SUM(CASE WHEN Type = 'Purchase' THEN Qty ELSE 0 END) OVER (ORDER BY Date ROWS BETWEEN UNBOUNDED PRECEDING AND CURRENT ROW),
SalesToDate = ABS(SUM(CASE WHEN Type = 'Sales' THEN Qty ELSE 0 END) OVER (ORDER BY Date ROWS BETWEEN UNBOUNDED PRECEDING AND CURRENT ROW))
FROM #transfer
)
SELECT Inventory.RowID,
Inventory.Area,
Inventory.Store,
Inventory.Item,
Inventory.Date,
Inventory.Type,
Inventory.Qty,
Season = CASE
WHEN Inventory.Season IS NULL
THEN ( SELECT TOP 1
PurchaseToSales.Season
FROM Inventory AS PurchaseToSales
WHERE PurchaseToSales.PurchaseToDate >= Inventory.SalesToDate
ORDER BY Inventory.Date
)
ELSE
Inventory.Season
END,
Inventory.PurchaseToDate,
Inventory.SalesToDate
FROM Inventory;
*更新*********
您需要一个关于数据的索引来帮助进行排序才能实现此功能。
可能：
CREATE NONCLUSTERED INDEX IX_Transfer ON #transfer(Store, Item, Date) INCLUDE(Area,Qty,Season,Type)
您应该在指定的索引上看到索引扫描。它不会是一个搜索，因为样本查询不会过滤任何数据，并且包含所有数据。
此外，您需要从SalesToDate的Partition By子句中删除Season。重置每个季节的销售额将使您的比较失败，因为滚动销售需要与滚动库存进行比较，以便您确定销售库存来源。
分区子句的另外两个提示：
-
请勿复制分区依据和分区依据。由于为每个分区重置聚合，因此分区字段的顺序无关紧要。充其量，有序分区字段将被忽略，最坏的情况可能导致优化器按特定顺序聚合字段。这对结果没有任何影响，但会增加不必要的开销。
-
确保您的索引与/ order by子句的分区定义相匹配。
索引应该是[分区字段，顺序无关紧要] + [排序字段，顺序需要匹配order by子句]。 在您的方案中，索引列应该在store，item和date上。如果date在store或item之前，则不会使用索引，因为优化器需要首先按store＆amp ;;处理分区。按日期排序前的项目。
如果数据中可能有多个区域，则索引和分区子句需要
索引：区域，商店，项目，日期
分区依据：区域，商店，按日期排序项目
答案 1 :(得分：0)
参考Wes的答案，提出的解决方案几乎没问题。它运作良好，但我注意到季节的分配不能正常工作，因为在我的场景中，库存应该由商店和商品本身计算和更新。我已经更新了添加一些调整的脚本。此外，我添加了一些新的“假”数据，以更好地了解我的场景以及它应该如何工作。
IF OBJECT_ID('tempdb..#transfer') IS NOT NULL
DROP TABLE #transfer;
GO
CREATE TABLE #transfer (
RowID INT IDENTITY(1, 1) PRIMARY KEY NOT NULL,
Area INT,
Store INT,
Item INT,
Date DATE,
Type VARCHAR(50),
Qty INT,
Season VARCHAR(50),
FlagSeason INT
);
INSERT INTO #transfer ( Area,
Store,
Item,
Date,
Type,
Qty,
Season,
FlagSeason
)
VALUES (1, 20, 300, '20150101', 'Purchase', 3, '2015-SpringSummer', 1),
(1, 20, 300, '20150601', 'Purchase', 4, '2016-SpringSummer', 1),
(1, 20, 300, '20150701', 'Sales', -1, NULL, NULL),
(1, 20, 300, '20150721', 'Sales', -2, NULL, NULL),
(1, 20, 300, '20150901', 'Sales', -1, NULL, NULL),
(1, 20, 300, '20160101', 'Sales', -1, NULL, NULL),
(1, 20, 300, '20170101', 'Purchase', 4, '2017-SpringSummer', 1),
(1, 20, 300, '20170125', 'Sales', -1, NULL, NULL),
(1, 20, 300, '20170201', 'Sales', -1, NULL, NULL),
(1, 20, 300, '20170225', 'Sales', -1, NULL, NULL),
(1, 21, 301, '20150801', 'Purchase', 4, '2017-SpringSummer', 1),
(1, 21, 301, '20150901', 'Sales', -1, NULL, NULL),
(1, 21, 301, '20151221', 'Sales', -2, NULL, NULL),
(1, 21, 302, '20150801', 'Purchase', 1, '2016-SpringSummer', 1),
(1, 21, 302, '20150901', 'Purchase', 1, '2017-SpringSummer', 1),
(1, 21, 302, '20151101', 'Sales', -1, NULL, NULL),
(1, 21, 302, '20151221', 'Sales', -1, NULL, NULL),
(1, 20, 302, '20150801', 'Purchase', 1, '2016-SpringSummer', 1),
(1, 20, 302, '20150901', 'Purchase', 1, '2017-SpringSummer', 1),
(1, 20, 302, '20151101', 'Sales', -1, NULL, NULL),
(1, 20, 302, '20151221', 'Sales', -1, NULL, NULL)
;
WITH Inventory
AS (SELECT *,
PurchaseToDate = SUM(CASE WHEN Type = 'Purchase' THEN Qty ELSE 0 END) OVER (partition by store, item ORDER BY store, item,Date ROWS BETWEEN UNBOUNDED PRECEDING AND CURRENT ROW),
SalesToDate = ABS(SUM(CASE WHEN Type = 'Sales' THEN Qty ELSE 0 END) OVER (partition by store, item,season ORDER BY store, item, Date ROWS BETWEEN UNBOUNDED PRECEDING AND CURRENT ROW))
FROM #transfer
)
SELECT Inventory.RowID,
Inventory.Area,
Inventory.Store,
Inventory.Item,
Inventory.Date,
Inventory.Type,
Inventory.Qty,
Season = CASE
WHEN Inventory.Season IS NULL
THEN ( SELECT TOP 1
PurchaseToSales.Season
FROM Inventory AS PurchaseToSales
WHERE PurchaseToSales.PurchaseToDate >= Inventory.SalesToDate
and PurchaseToSales.Item = inventory.item --//Added
and PurchaseToSales.store = inventory.store --//Added
and PurchaseToSales.Area = Inventory.area --//Added
ORDER BY Inventory.Date
)
ELSE
Inventory.Season
END,
Inventory.PurchaseToDate,
Inventory.SalesToDate
FROM Inventory
这里输出：
经过这些调整后，它运行正常，但是如果我使用6百万行数据表中的实际数据切换假数据，则查询变得非常慢（每分钟提取约400行），因为插入这些检查在子查询的where子句中：
WHERE PurchaseToSales.PurchaseToDate >= Inventory.SalesToDate
and PurchaseToSales.Item = inventory.item --//Added
and PurchaseToSales.store = inventory.store --//Added
and PurchaseToSales.Area = Inventory.area --//Added
我尝试用“交叉应用”功能替换子查询，但没有任何改变。我想念一些事吗？
提前致谢
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