php - 如何在mysql中具有外键属性的表中插入新记录

Question

由于客户表只有一条记录，因此该语句有什么问题

INSERT INTO CART (Cartid,custid,Pid)
VALUES ('2',SELECT(custid from CUSTOMERS), SELECT (Pid from Products where Pname ='shirts'))

Answer 1

确保购物车表id为主键且auto_increment。获取客户 ID 并存储在变量中。你可以尝试类似的东西

INSERT INTO CART (Cartid,custid,Pid) VALUES ('', SELECT custid from CUSTOMERS  WHERE custid = '$customer_id'),(SELECT Pid FROM Products WHERE Pname = 'shirts' LIMIT 1));