Question

这是我写的触发器。

DELIMITER //
create trigger after_insert_bid
after insert on Bid
for each row
when exists(
    select * 
    from Item
    where ItemID = new.ItemID)
begin
update Item set Item.currently = NEW.amount where Item.itemID = NEW.itemID;
end;//
DELIMITER ;

它有一个错误：

ERROR 1064 (42000): You have an error in your SQL syntax; check the manual that corresponds to your MySQL server version for the right syntax to use near 'when exists(
SELECT *
FROM Item
WHERE ItemID = new.ItemID
)
begin
UPDATE Item SE' at line 4
mysql> end;

我是mysql的新手，我知道这是一个简单的问题，但我真的不知道如何找到错误，谢谢！

mysql版本是5.1.73

Answer 1

您无需检查项目表中是否存在itemid，只需直接更新项目表。如果Item表中不存在ItemID，则不会更新该表。

for each row 
begin
  update Item set Item.currently = NEW.amount where Item.itemID = NEW.itemID;
end

mysql：ERROR 1064（42000）触发器

1 个答案: