MySQL 在插入触发器之前修改行值

Question

我正在处理类似 Netflix 的数据库。我想创建一个触发器，只要将新内容添加到数据库中就会调用它。它应该做的是，如果内容的名称类似于“The Return of the King”，则将其替换为“Return of the King, The”。

目前我有以下触发器：

DROP TRIGGER IF EXISTS `UpdateContentName`;
       CREATE DEFINER=`root`@`localhost` TRIGGER `UpdateContentName` 
       BEFORE INSERT ON `content` FOR EACH ROW  
       BEGIN
            SET NEW.`name_content` = 'teeeeeest' 
            WHERE content.name_content LIKE = "The %";
        END

但我收到以下错误消息：

MySQL said: #1064 - 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 'WHERE content.name_content LIKE = "The %"; END' at line 5

看起来问题出在 WHERE content.name_content LIKE = "The %"; 行，因为它在没有它的情况下也能正常工作，但我不明白我应该做什么...我花了几个小时试图解决这个问题但没有设法找到解决方案...

总而言之，我想实现如下目标：

If(name_content.contains("The %")) 
   //name_content in the form "name of the content, The" instead of "The name of the content"

感谢您的帮助！ :)

Answer 1

您需要在设置之前检查条件

DELIMITER $$
DROP TRIGGER IF EXISTS `UpdateContentName`;
CREATE DEFINER=`root`@`localhost` TRIGGER `UpdateContentName` 
BEFORE INSERT ON `content` FOR EACH ROW  
BEGIN
    IF  NEW.name_content LIKE "The %" THEN
        SET NEW.`name_content` = 'teeeeeest';
    END IF;     
END$$
DELIMITER ;

CREATE tABLE content( name_content varchar(100))

CREATE  TRIGGER `UpdateContentName` 
BEFORE INSERT ON `content` FOR EACH ROW  
BEGIN
    IF  NEW.name_content LIKE "The %" THEN
        SET NEW.`name_content` = 'teeeeeest';
    END IF;     
END

INSERT INTO content VALUES('The AbC')

SELECT * FROM content

| name_content |
| :----------- |
| teeeeeest    |

db<>fiddle here

MySQL 在插入触发器之前修改行值

MySQL modify row value on before insert trigger

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