如何删除其他表中的条件的行（sql）

Question

CUSTOMER ( Cid, CName, City, Discount )
AGENT ( Aid, AName, City, Percent )  
PRODUCT ( Pid, PName, City, Quantity, Price )  
ORDERS ( OrderNo, Month, Cid, Aid, Pid, OrderedQuantity, Cost )

Q- 删除居住在纽约市的代理商发出的所有订单。

Answer 1

您可以使用in运算符：

DELETE
FROM   orders
WHERE  aid IN (SELECT aid
               FROM   agent
               WHERE  city = 'New York')