mysql – 在触发器信号语句附近使用concat语法错误

请帮我学习MySQL 5.6的语法.

出于某种原因,我得到错误：

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 '('WRONG SOCIAL: ', new.social);
        end if;
        if not (new.photo is nul'

尝试运行此SQL代码时：

create table table_social (
        sid varchar(250) primary key,
        auth char(32) not null,
        social integer,               -- to be checked by triggers
        female boolean,
        given varchar(250) not null,
        family varchar(250) null,
        photo varchar(1000) null,     -- to be checked by triggers
        place varchar(250) null,
        ip varchar(250) not null,
        uid integer not null references 
            table_users(uid) on delete cascade
);

delimiter //

create trigger social_insert_trigger before insert on table_social
for each row begin
        if new.social < 0 OR new.social > 6 then
                signal sqlstate '45000' 
                set message_text = concat('WRONG SOCIAL: ', new.social);
        end if;
        if not (new.photo is null OR new.photo regexp '^https?://') then
                signal sqlstate '45000' 
                set message_text = concat('WRONG PHOTO: ', new.photo);
        end if;
end
//

create trigger social_update_trigger before update on table_social
for each row begin
        if new.social < 0 OR new.social > 6 then
                signal sqlstate '45000' 
                set message_text = concat('WRONG SOCIAL: ', new.social);
        end if;
        if not (new.photo is null OR new.photo regexp '^https?://') then
                signal sqlstate '45000' 
                set message_text = concat('WRONG PHOTO: ', new.photo);
        end if;
end
//

我尝试删除concat,用双引号替换单引号,将信号线分成两部分(如上所述)和后部 – 但仍然无法找出,有什么问题.

解决方法:

测试此代码：

drop table if EXISTS table_social;
create table table_social (
        sid varchar(250) primary key,
        auth char(32) not null,
        social integer,               -- to be checked by triggers
        female boolean,
        given varchar(250) not null,
        family varchar(250) null,
        photo varchar(1000) null,     -- to be checked by triggers
        place varchar(250) null,
        ip varchar(250) not null,
        uid integer not null references 
            table_users(uid) on delete cascade
);

delimiter //

create trigger social_insert_trigger before insert on table_social
for each row begin
        if new.social < 0 OR new.social > 6 then
                set @message_text = concat('WRONG SOCIAL: ', new.social);
                signal sqlstate '45000'
                set MESSAGE_TEXT = @message_text;
        end if;
        if not (new.photo is null OR new.photo regexp '^https?://') then
                set @message_text = concat('WRONG PHOTO: ', new.photo);
                signal sqlstate '45000' set message_text = @message_text;
        end if;
end
//

create trigger social_update_trigger before update on table_social
for each row begin
        if new.social < 0 OR new.social > 6 then
                set @message_text = concat('WRONG SOCIAL: ', new.social);
                signal sqlstate '45000' 
                set message_text = @message_text;
        end if;
        if not (new.photo is null OR new.photo regexp '^https?://') then
                set @message_text = concat('WRONG PHOTO: ', new.photo);
                signal sqlstate '45000' 
                set message_text = @message_text;
        end if;
end
//

它不理解SIGNAL SQLSTATE SET message_text中的CONCAT()

标签：mysql-5-6,concat,mysql,syntax,trigger
来源： https://codeday.me/bug/20190806/1599265.html