根据订单更新库存表数量

Question

我在创建一个sql语句时遇到问题，该语句将根据Inbound orders表更新Inventory表。

入站

OrderID  ProductID  Description  ShipQty
001      2          Apple        3
002      4          Orange       4
003      1          Grape        1
004      2          Apple        6
005      5          Strawberry   3
006      3          Pear         1
007      1          Grape        2

INVENTORY

ProductID  Description  Qty
1          Grape        10
2          Apple        10
3          Pear         10
4          Orange       10
5          Strawberry   10

更新后的库存应该是什么样的

ProductID  Description  Qty
1          Grape        13
2          Apple        19
3          Pear         11
4          Orange       14
5          Strawberry   13

Answer 1

你可以试试这个：

UPDATE INVENTORY
SET Qty = Qty + (SELECT SUM(ShipQty) FROM INBOUND WHERE ProductID = INVENTORY.ProductID)

Answer 2

尝试以下：

update INVENTORY
set qty = qty + TotalQty
from (
select INBOUND.ProductID, sum(shipqty) as TotalQty
from INBOUND
group by INBOUND.ProductID
) as a
where a.ProductID = INVENTORY.ProductID