Sql server Update语句包含来自另一个表的子查询

我正在尝试更新表中的一列。目标是获取当前值并从其他表中减去该值。以下是我所看到的：

update LS   
    set LS.Quantity = (LS.Quantity - 
    ( 
        select top 1 LSM.Quantity 
        from tblLocationStockMovement LSM
            join tblLocation L on L.ID=LSM.LocationID
            join tblStock S on S.ID=LSM.StockID
            join tblLocationStock LS on LS.StockID=LSM.StockID
        where 
            LSM.StockID=LS.StockID 
            and MoveTypeID=16
            and dateadd(DAY, DATEDIFF(day,0,DateCreated),0)='2016-08-30 00:00:00.00')
    )

from tblLocationStock LS    
    join tblLocation L on L.ID=LS.LocationID
    join tblStock S on S.ID=LS.StockID
    join tblLocationStockMovement LSM on LS.StockID=LSM.StockID

tbllocationstockmove

表中有我需要从

tblLocationStock

表中减去的值。它们都可以使用

StockID

连接到

tblStock

。我希望它能减去两个表中引用的同一只股票的价值。现在它只是对每一个项目做相同的编号

我可能不需要最后的

join

s，我只是用它来添加一个

where

来测试一个特定的项目，然后再对每个项目进行测试。你知道我哪里做错了吗

编辑：谢谢David修改了我的格式。我没有经常使用这个网站，所以我不太熟悉发布东西的正确方式

编辑2：

你们三个都有一个相似的想法，奇怪的是它有时会起作用

以下是我正在运行的内容：

update LS
     set LS.Quantity=(ISNULL(LS.Quantity,0)-ISNULL(LSM.Quantity,0))
         from tblLocationStock LS
             join tblLocation L on L.ID=LS.LocationID
             join tblStock S on S.ID=LS.StockID
             join tblLocationStockMovement LSM on LSM.StockID=S.ID
         where L.LongDescription='Cafe'
             and MoveTypeID=2
             and PLU = 715 

问题是结果改变了，我不知道为什么

select LSM.Quantity
from tblLocationStockMovement LSM
     join tblLocation L on L.ID=LSM.LocationID
     join tblStock S on S.ID=LSM.StockID
where L.LongDescription='Cafe'
    and PLU=715
    and MoveTypeID=2

结果总是120

 select LS.Quantity
    from tblLocationStock LS
        join tblLocation L on L.ID=LS.LocationID
        join tblStock S on S.ID=LS.StockID
    where L.LongDescription='Cafe'
        and PLU = 715

结果总是53。因此，您希望update语句的结果始终是-67。有时会，但有时我会得到5，-43或29。答案会有不同的原因吗？

试试这个：

update LS
set LS.Quantity=LS.Quantity-LSM.Quantity
from tblLocationStock LS
    join tblLocation L on L.ID=LS.LocationID
    join tblStock S on S.ID=LS.StockID
    join tblLocationStockMovement LSM on LS.StockID=LSM.StockID
where LSM.movetypeid=16
    and LSM.datecreated = '08/30/2016'

update LS   
    set LS.Quantity = ISNULL(LS.Quantity,0) - ISNULL(LSM.Quantity,0)
from tblLocationStock LS    
join tblLocation L on L.ID=LS.LocationID
join tblStock S on S.ID=LS.StockID
join tblLocationStockMovement LSM on LS.StockID=LSM.StockID
    and MoveTypeID=16
    and dateadd(DAY, DATEDIFF(day,0,DateCreated),0)='2016-08-30 00:00:00.00'

您也可以尝试以下方法：

UPDATE LS   
    SET LS.Quantity = (LS.Quantity-LSM.Quantity)
FROM tblLocationStockMovement LSM
JOIN tblLocation L ON L.ID=LSM.LocationID
JOIN tblStock S ON S.ID=LSM.StockID
JOIN tblLocationStock LS ON LS.StockID=LSM.StockID
WHERE LSM.StockID=LS.StockID 
    AND MoveTypeID=16
    AND dateadd(DAY, DATEDIFF(DAY,0,DateCreated),0)='2016-08-30 00:00:00.00')

试试这个：

update LS
set LS.Quantity=LS.Quantity-LSM.Quantity
from tblLocationStock LS
    join tblLocation L on L.ID=LS.LocationID
    join tblStock S on S.ID=LS.StockID
    join tblLocationStockMovement LSM on LS.StockID=LSM.StockID
where LSM.movetypeid=16
    and LSM.datecreated = '08/30/2016'

update LS   
    set LS.Quantity = ISNULL(LS.Quantity,0) - ISNULL(LSM.Quantity,0)
from tblLocationStock LS    
join tblLocation L on L.ID=LS.LocationID
join tblStock S on S.ID=LS.StockID
join tblLocationStockMovement LSM on LS.StockID=LSM.StockID
    and MoveTypeID=16
    and dateadd(DAY, DATEDIFF(day,0,DateCreated),0)='2016-08-30 00:00:00.00'