SQL子查询返回多个值，没有更新它工作正常

Question

这个查询工作，并返回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 

这也是260行：

select * from SHIPMENTPRODUCTS where shipmentid = 1234 

但下一个给：

Msg 512，Level 16，State 1，Line 2 子查询返回的值超过1个。当子查询遵循=，！=，<，< =，>，> =或当子查询用作表达式时，这是不允许的。

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 

，我认真没有任何线索。也不知道如何开始这个。区别仅在于查询1是独立的，查询2是包装在更新语句中的查询1。

Answer 1

我想这是你正在尝试做的：

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