SQL子查詢返回多個值，沒有更新它工作正常

Question

這個查詢工作，並返回260行：

SELECT PRODUCTS.ProductResalePrice * ((100 - isnull((select discountperc from CUSTOMERDISCOUNT where CustomerID = CUSTOMERS.CustomerID and CategoryID = products.CategoryID), 0))/100) AS incDisc 
FROM PRODUCTS 
INNER JOIN SHIPMENTPRODUCTS op ON PRODUCTS.ProductID = op.ProductID 
INNER JOIN SHIPMENTS ON op.shipmentid = shipments.shipmentid 
INNER JOIN CUSTOMERS ON shipments.CustomerID = CUSTOMERS.CustomerID 
left JOIN CUSTOMERDISCOUNT ON CUSTOMERS.CustomerID = CUSTOMERDISCOUNT.CustomerID 
    AND PRODUCTS.CategoryID = CUSTOMERDISCOUNT.CategoryID 
WHERE op.shipmentid = 1234 

這也是260行：

select * from SHIPMENTPRODUCTS where shipmentid = 1234 

但下一個給：

Msg 512，Level 16，State 1，Line 2 子查詢返回的值超過1個。當子查詢遵循=，！=，<，< =，>，> =或當子查詢用作表達式時，這是不允許的。

update SHIPMENTPRODUCTS set SoldFor = 
    (SELECT PRODUCTS.ProductResalePrice * ((100 - isnull((select discountperc from CUSTOMERDISCOUNT where CustomerID = CUSTOMERS.CustomerID and CategoryID = products.CategoryID), 0))/100) AS incDisc 
     FROM PRODUCTS 
     INNER JOIN SHIPMENTPRODUCTS op ON PRODUCTS.ProductID = op.ProductID 
     INNER JOIN SHIPMENTS ON op.shipmentid = shipments.shipmentid 
     INNER JOIN CUSTOMERS ON shipments.CustomerID = CUSTOMERS.CustomerID 
     left JOIN CUSTOMERDISCOUNT ON CUSTOMERS.CustomerID = CUSTOMERDISCOUNT.CustomerID 
       AND PRODUCTS.CategoryID = CUSTOMERDISCOUNT.CategoryID 
     WHERE op.ProductID = SHIPMENTPRODUCTS.productid and op.shipmentid = SHIPMENTPRODUCTS.shipmentid) 
where SHIPMENTPRODUCTS.shipmentid = @shipmentId 

，我認真沒有任何線索。也不知道如何開始這個。區別僅在於查詢1是獨立的，查詢2是包裝在更新語句中的查詢1。

Answer 1

我想這是你正在嘗試做的：

update SHIPMENTPRODUCTS 
set SoldFor = PRODUCTS.ProductResalePrice * ((100 - isnull((select discountperc from CUSTOMERDISCOUNT where CustomerID = CUSTOMERS.CustomerID and CategoryID = products.CategoryID), 0))/100) 
FROM PRODUCTS 
INNER JOIN SHIPMENTPRODUCTS op ON PRODUCTS.ProductID = op.ProductID 
INNER JOIN SHIPMENTS ON op.shipmentid = shipments.shipmentid 
INNER JOIN CUSTOMERS ON shipments.CustomerID = CUSTOMERS.CustomerID 
left JOIN CUSTOMERDISCOUNT ON CUSTOMERS.CustomerID = CUSTOMERDISCOUNT.CustomerID 
    AND PRODUCTS.CategoryID = CUSTOMERDISCOUNT.CategoryID 
WHERE op.ProductID = SHIPMENTPRODUCTS.productid and op.shipmentid = SHIPMENTPRODUCTS.shipmentid) 
where SHIPMENTPRODUCTS.shipmentid = @shipmentId