MySQL 过程不能同时使用 select 和 delete答案

【问题标题】：MySQL procedure not working with both select and deleteMySQL 过程不能同时使用 select 和 delete
【发布时间】：2021-10-26 19:14:47
【问题描述】：

我创建了一个过程，使用车辆编号输入从车辆表中获取车辆 ID，然后删除该车辆 ID 的预订记录，最后删除车辆表中的条目......但是在创建过程时我在第 7 行收到错误消息 Error Code: 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 '' at line 7 请帮我确定问题... 提前致谢

CREATE PROCEDURE `DeleteVehicleWithBookings`(IN vehicleNo VARCHAR(10))
BEGIN

    #get vehicle id
    select @vid = vehicleID
    from vehicle
    where vehicle_no = vehicleNo;

    #delete booking
    delete from booking where vehicleID = vid;
    
    #delete vehicle
    delete from vehicle where vehicle_no = vehicleNo;
END 
DELIMITER ;

【问题讨论】：

1) SET @vid = vehicleID .... 2) where vehicleID = @vid;

标签： mysql sql select procedure

【解决方案1】：

首先，我建议您为参数添加前缀，以便更清楚地区分它们与列名。

那么，您没有正确分配和使用变量。所以，你的意图更像是这样的：

CREATE PROCEDURE `DeleteVehicleWithBookings`(
    IN in_vehicleNo VARCHAR(10)
)
BEGIN
    #get vehicle id
    select @vid := vehicleID
    from vehicle
    where vehicle_no = in_vehicleNo;

    #delete booking
    delete from booking where vehicleID = @vid;
    
    #delete vehicle
    delete from vehicle where vehicle_no = in_vehicleNo;
END 
DELIMITER ;

不过，前两个语句可以不使用变量来编写：

#delete booking
delete b from booking b
    where b.vehicleID = (select v.vehicleID
                         from vehicle v
                         where v.vehicle_no = in_vehicleNo
                        );

而且，您可能可以定义级联删除外键约束并完全消除存储过程。

【讨论】：