Question

我感到很尴尬，我必须来这里寻求帮助，但是在我学习之前肯定有很多，似乎mySQL语法错误信息与灰熊的教皇帽子一样有用。附件是我第一次尝试为汽车公司数据库编写触发器。表can_lease将员工的ID与汽车模型的ID相关联。预计触发器将实施两个规则：1）最多可以有10个与1名员工相关的汽车模型，2）员工必须属于租赁类型（有一个“租赁”栏目必须等于“Y”）。

因此，目标是触发器捕获违反此规则的行为并发送信号和解释违规的消息。我只是不确定错误是什么，但我也会附上相关的错误消息。

create procedure can_lease_check (eid int)
begin
        declare can_lease_too_many_models condition for sqlstate '90001';
        if ((select count(rent_model_id) from can_lease where emp_id = eid) >= 10)
        then signal sqlstate '90001' set message_text = 'employee can lease at most 10 rent models.';

        declare can_lease_not_leaser for sqlstate '90002';                                                                                           
        if not (select leasing from employer where employer.emp_id = eid) == 'Y'                                                                     
        then signal sqlstate '90002' set message_text = 'employee must be of type "leasing"';
end;

delimiter $$
create trigger can_lease_insert_trigger
after insert on can_lease
for each row begin
    call can_lease_check(new.emp_id);
end;
$$

create trigger can_lease_update_trigger
after update on can_lease
for each row begin
    call can_lease_check(new.emp_id);
end;
$$

以下是错误消息：

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 '' at line 3
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 'if ((select count(rent_model_id) from can_lease where emp_id = eid) >= 10)
    then' at line 1
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 'end' at line 1

感谢您的帮助！我也非常感谢你对调试这类事情提出的任何建议。来自gcc告诉我至少某些关于我的代码错误的原因，这是一个非常外国的过程！

编辑：我意识到我应该将分隔符更改移动到程序之上。我没有得到它，但除了其中一个错误之外的所有错误。目前，错误是

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 'if (select count(rent_model_id) from can_lease where emp_id = eid) == 10
    then s' at line 4

Answer 1

第一个;和begin关键字之间的分号（end）是罪魁祸首。只需将原始create块与DELIMITER括起来，如下所示。我在我的示例中使用#作为分隔符，并且我认识到您使用$$，但不会产生任何差异。

DELIMITER #
create procedure can_lease_check (eid int)
begin
    declare can_lease_too_many_models condition for sqlstate '90001';
    if ((select count(rent_model_id) from can_lease where emp_id = eid) >= 10)
    then signal sqlstate '90001' set message_text = 'employee can lease at most 10 rent models.';

    declare can_lease_not_leaser for sqlstate '90002';                                                                                           
    if not (select leasing from employer where employer.emp_id = eid) == 'Y'                                                                     
    then signal sqlstate '90002' set message_text = 'employee must be of type "leasing"';
end#

此外，如果您像我一样（end#）结束，或者像您一样，使用end关键字后面的分号结束，则没有任何区别：

end;
#

mysql中的语法错误，包括过程，触发器和信号

1 个答案: