Question

我之前已经问过这个问题，我想详细说明一下。

我有以下触发器（有点像我之前问过的那个）：

CREATE TRIGGER trigger_test1
BEFORE INSERT ON test1 
FOR EACH ROW 
  SET NEW.OriginIndex = (SELECT index1 FROM cities WHERE city = NEW.Origin),
    NEW.DestinationIndex = (SELECT index1 FROM cities WHERE city =NEW.Destination);

这部分效果很好。现在我想将OriginIndex和DestinationIndex相乘并将其存储在另一列中（假设为'Multiplication'）。

我这样做了：

CREATE TRIGGER trigger_test1
BEFORE INSERT ON test1 
FOR EACH ROW 
  SET NEW.OriginIndex = (SELECT index1 FROM cities WHERE city = NEW.Origin),
    NEW.DestinationIndex = (SELECT index1 FROM cities WHERE city =NEW.Destination),
        NEW.Multiplication = (SELECT NEW.OriginIndex*NEW.DestinationIndex);

这给出了一个错误'这个版本的MySQL还不支持'多个触发器，具有相同的一个表的动作时间和事件''。

我该怎么处理这个问题？

Answer 1

我认为你可以使用

DELIMITER //
CREATE TRIGGER trigger_test1
BEFORE INSERT ON test1 
BEGIN
FOR EACH ROW 
SET NEW.OriginIndex = (SELECT index1 FROM cities WHERE city = NEW.Origin);
SET NEW.DestinationIndex = (SELECT index1 FROM cities WHERE city =NEW.Destination);
SET NEW.Multiplication = (NEW.OriginIndex*NEW.DestinationIndex);
END//

我希望这有帮助。

触发器在mysql中乘以'基于触发器的列'

1 个答案: