Question

如果答案在这里显而易见，请原谅我，但我已经被困了好几天;我在下面的查询不成功。

如果＆＃39;零售商＆＃39;报告销售数据，但不报告某一天的库存值，我想使用前一天的值更新该缺失值。

这是一个示例表：

Retailer    Date                      ItemID   Sold   Inventory
Joe's       2017-10-30 00:00:00.000   111111   10     0
Joe's       2017-10-29 00:00:00.000   111111   10     999999
Mary's      2017-10-30 00:00:00.000   123123   10     0
Mary's      2017-10-29 00:00:00.000   123123   10     888888
Betty's     2017-10-30 00:00:00.000   111111   10     499990
Betty's     2017-10-29 00:00:00.000   111111   10     500000

以下是我尝试使用的查询：

SET T1.Inventory = (SELECT T2.Inventory
                   FROM [dbo].[TEST] T2
                   WHERE CAST(T2.Date AS DATE) = CONVERT(date,getDate()-2))

FROM [dbo].[TEST] T1
WHERE Inventory = '0'

Answer 1

使用DATEADD功能代替getDate()-2

如果你想要今天前一天，你应该使用GetDate并减去1，而不是2。

如果您想要在同一零售商处查看记录的前一天，那么您应该使用t1.Date并确保已关联子查询：

SET T1.Inventory = (SELECT T2.Inventory
                   FROM [dbo].[TEST] T2
                   WHERE CAST(T2.Date AS DATE) = DATEADD(day,-1,CONVERT(date,T1.Date))
                   AND t1.Retailer=t2.Retailer
                   )
 ...

Answer 2

毫无疑问，更新库存列时遇到困难的原因是该表缺少一个唯一的列，大多数人认为该列在任何数据库表中都是绝对必要的。所以我添加了一个标识列RID作为唯一的行ID。

ALTER TABLE T1 ADD RID INT IDENTITY(1,1)

DECLARE @RID INT = (SELECT MIN(RID) FROM T1 WHERE Inventory = 0)
DECLARE @INVZERO INT = (SELECT COUNT(*) FROM T1 WHERE Inventory = 0)
WHILE @INVZERO > 0
BEGIN
UPDATE T1 SET INVENTORY =
(
SELECT INVENTORY FROM T1
WHERE RETAILER = (SELECT RETAILER FROM T1 WHERE RID = @RID)
AND [DATE] = DATEADD(DAY,-1,(SELECT [DATE] FROM T1 WHERE RID = @RID))
)
WHERE RID = @RID
SET @RID = (SELECT MIN(RID) FROM T1 WHERE Inventory = 0 AND RID > @RID)
SET @INVZERO = (SELECT COUNT(*) FROM T1 WHERE Inventory = 0)
END

SELECT * FROM T1

使用UPDATE + SET将值更改为另一个日期的值

2 个答案: