MySql 错误：结果包含多于一行

Question

我有错误：Result consisted of more than one row but i can't find out it.

条目 id_user 在其表中只有一条记录。

程序：

CREATE DEFINER=`root`@`localhost` PROCEDURE `delete_user_deep`(id_user int(11))
BEGIN

declare nome_loc varchar(45);
declare cognome_loc varchar(45);

select nome,cognome
into nome_loc,cognome_loc
from user
where id_user=id_user;

delete from Radius.radcheck where username in (
    select mac_address from machine where id_user =id_user);

delete from Radius.radreply where username in (
    select mac_address from machine where id_user =id_user);

delete from machine_ip where id_machine in (
    select id_machine from machine where id_user=id_user);

delete from machine where id_user = id_user;

delete from document where id_user=id_user;

delete from user where id_user=id_user;

insert into log_generic values(
                    NULL,
                    'USER',
                    'Delete User Deep',
                    (select concat ('User: ',id_user,' Name: ',cognome_loc,' Prename: ',nome_loc)),
                    now());

END

Answer 1

问题出在这句话中：

select nome,cognome
into nome_loc,cognome_loc
from user
where id_user=id_user;

如果多于一行，这将返回错误。错误记录在here。

这是因为参数名与列名相同造成的。 id_user 指的是比较两边的列。

查询应如下所示：

select nome, cognome
into nome_loc, cognome_loc
from user
where id_user = param_id_user;

总是为参数和变量名添加前缀以区别于列名。