Mysql SQL'；插入触发器后'；投诉未知列'；currentId'；在字段列表中，它是游标

我有两张桌子

create table comments (
    id int auto_increment primary key,
    task_id int not null,
    foreign key fk_comment_task(task_id) references tasks(id),
    user int not null,
    foreign key fk_comment_user(user) references users(id),
    comment varchar(1000) not null,
    comment_date date not null,
    viewed tinyint(1) not null default 0,
    deleted tinyint(1) not null default 0   
) engine = InnoDB;

第二个：

create table viewed_comments (
    id int auto_increment primary key,
    comment int not null,
    foreign key fk_viewed_comment(comment) references comments(id),
    viewer int not null,
    foreign key fk_viewed_viewer(viewer) references users(id),
    unread tinyint(1) not null default 0,
    deleted tinyint(1) not null default 0
) engine = InnoDB;

我想创建一个触发器，当注释插入“comments”表时，“viewsed_comments”表为所有用户（提交注释的用户除外）创建该注释的行

目前，我有一个触发器：

delimiter |
create trigger ins_views after insert on comments 
for each row 
    begin
        DECLARE finished INT DEFAULT 0;
        DECLARE id INT DEFAULT 0;

        DECLARE currentId CURSOR FOR SELECT id FROM users WHERE id != NEW.user;

        DECLARE CONTINUE HANDLER 
            FOR NOT FOUND SET finished = 1;

        OPEN currentId;

        update_views_loop: LOOP
            FETCH currentId INTO id;
            IF finished = 1 THEN LEAVE update_views_loop;

            END IF;
            INSERT INTO viewed_comments (comment, viewer) VALUES (NEW.id, currentId);   

        END LOOP update_views_loop;

     CLOSE currentId;

    END;
|

delimiter ;

当我插入诸如“插入注释（任务id、用户、注释、注释日期）”的值（24、4、“测试”、“2018-3-5”）时；作为一个例子，我得到了以下响应。 错误1054（42S22）：光标“字段列表”中的未知列“currentId”。我该如何解决这个问题

 INSERT INTO viewed_comments (comment, viewer) VALUES (NEW.id, id);

因为您将值读入变量id。请使用此值，而不是光标

 FETCH currentId INTO id;