添加新行时在Mysql错误中创建触发器

Question

我有两个带有列的表model_detail

`id``model_id``productName``Color``Available_Quantity`

和model_stock与列

`id``model_detail_id``entry_date``amount`

model_detail_id是指向model_detail（ id ）表的外键，我想在添加新的model_stock时更新model_detail表的Available_Quantity ，并且我尝试过类似的操作

CREATE TRIGGER Update_model_stock AFTER INSERT ON model_stock
FOR EACH ROW 
BEGIN
UPDATE model_detail
SET Available_Quantity= Available_Quantity + NEW.amount
WHERE model_detail.id = NEW.model_stock.model_detail_id;
END

但是当我在model_stock表中添加一行时，我得到了这样的错误

SQL query:
INSERT INTO `model_stock` (`id`, `model_detail_id`, `entry_date`, `amount`) 
VALUES (NULL, '2', '2017-07-11', '20')

我收到的错误消息：

MySQL说：文档＃1054-“ where子句”中的未知列“ NEW.model_stock.model_detail_id”

Answer 1

您不能在NEW关键字后面添加表名：

...
WHERE model_detail.id = NEW.model_detail_id;
...