Question

我有两个表，并希望在删除故障单时创建一个在ticket_reply上删除的触发器：

票：

PHP_VERSION=$(php -v | tail -r | tail -n 1 | cut -d " " -f 2 | cut -c 1-3)
cd /usr/local/etc/php/$PHP_VERSION/
# cd /usr/local/etc/php/7.1/

并且ticket_reply：

+-------------+-----------------+------+-----+---------+----------------+
| Field       | Type            | Null | Key | Default | Extra          |
+-------------+-----------------+------+-----+---------+----------------+
| id          | int(8) unsigned | NO   | PRI | NULL    | auto_increment |
| user_id     | int(8) unsigned | NO   | MUL | NULL    |                |
| status      | varchar(6)      | NO   |     | opened  |                |
| subject     | varchar(100)    | NO   | MUL | NULL    |                |
| message     | text            | NO   |     | NULL    |                |
+-------------+-----------------+------+-----+---------+----------------+

我的触发器：

+-----------+-----------------+------+-----+---------+----------------+
| Field     | Type            | Null | Key | Default | Extra          |
+-----------+-----------------+------+-----+---------+----------------+
| id        | int(8) unsigned | NO   | PRI | NULL    | auto_increment |
| user_id   | int(8) unsigned | NO   |     | NULL    |                |
| ticket_id | int(8) unsigned | NO   | MUL | NULL    |                |
| message   | text            | NO   |     | NULL    |                |
+-----------+-----------------+------+-----+---------+----------------+

我收到错误消息：CREATE TRIGGER `ticket_delete` BEFORE DELETE ON ticket FOR EACH ROW BEGIN DELETE FROM ticket_reply WHERE ticket_reply.ticket_id = ticket.id; END

为什么呢？

感谢。

Answer 1

使用分隔符，或者跳过BEGIN / END：

DELIMITER $
CREATE TRIGGER `ticket_delete` BEFORE DELETE ON ticket
FOR EACH ROW
BEGIN
DELETE FROM ticket_reply
    WHERE ticket_reply.ticket_id = ticket.id;
END $
DELIMITER ;

或

CREATE TRIGGER `ticket_delete` BEFORE DELETE ON ticket
FOR EACH ROW
DELETE FROM ticket_reply
    WHERE ticket_reply.ticket_id = ticket.id;

它会使语法错误消失;但是你的触发器是错误的，实际上它应该是

CREATE TRIGGER `ticket_delete` BEFORE DELETE ON ticket
FOR EACH ROW
DELETE FROM ticket_reply
    WHERE ticket_reply.ticket_id = OLD.id;

（请注意OLD.id而不是ticket.id）。

在错误之前触发ON

1 个答案: