mysql - 无法在触发器中设置变量

Question

我正在尝试在触发器中设置一个变量，该变量是表中的最新条目。但是，PHPMyAdmin 注意到 SET clicked_campaign_id = 行存在错误。我没有看到这里的问题。

CREATE TRIGGER tr_user_action_click 
AFTER INSERT ON users_click FOR EACH ROW
BEGIN
    DECLARE clicked_campaign_id int

    SET clicked_campaign_id = 
    (SELECT campaignId 
    FROM users_click 
    WHERE id = (SELECT max(id) FROM users_click));

    Update onlineportal.`campaigns`
    SET `clicks` = `clicks` + 1
    WHERE id = clicked_campaign_id;
END

是否有不同的方法来设置变量...？

Answer 1

您必须在phpMyAdmin中设置DELIMITER，如图所示:

然后，创建触发器:

CREATE TRIGGER `tr_user_action_click` AFTER INSERT ON `users_click`
FOR EACH ROW
BEGIN
    DECLARE `clicked_campaign_id` INT;

    SET `clicked_campaign_id` = 
    (SELECT `campaignId` 
    FROM `users_click`
    WHERE `id` = (SELECT max(`id`) FROM `users_click`));

    UPDATE `onlineportal`.`campaigns`
    SET `clicks` = `clicks` + 1
    WHERE `id` = `clicked_campaign_id`;
END//