mysq触发器中的自增id问题

[lihuan2008a]

CREATE TABLE `test` (
  `id` bigint(20) NOT NULL AUTO_INCREMENT,
  `order` varchar(255) DEFAULT NULL,
  `des` varchar(255) DEFAULT NULL,  
  PRIMARY KEY (`id`)
) ENGINE=InnoDB AUTO_INCREMENT=1 DEFAULT CHARSET=utf8;

create trigger trigger_test before insert on test
for each row
begin
set new.order =concat('Ord',lpad(cast(new.id as char),5,'0'));
end;不行啊，得到的是00000

想要如下效果
id order des
1 00001
2 00002
咋么才能做到啊

[wwwwb]

`id` bigint(20) zerofill NOT NULL AUTO_INCREMENT 试试

[lihuan2008a]

zerofill这只是在id前填充0,
我需要的是order后面的数要和id保持一致

insert into test(des) values('中国'); 
select * from test;

[wwwwb]

set new.order =concat('Ord',right(concat('0000',new.id),5))

[lihuan2008a]

引用 3 楼 wwwwb 的回复:

set new.order =concat('Ord',right(concat('0000',new.id),5))

create trigger trigger_test before insert on test
for each row
begin
set new.order =concat('Ord',right(concat('0000',new.id),5));
end;

insert into test(des) values('中国'); 
select * from test;

这样也不行哦，和原来一样的仍是ord00000 只有在insert into test(id) values(6); 这样才可以 而这样的insert into test(des) values('中国'); new.id好像就取不到id

[ACMAIN_CHM]

MYSQL中没办法。 在BEFORE INSERT中无法得到ID的值。 而在ＡＦＴＥＲ　ＩＮＳＥＲＴ中又无法更改记录。

[dong_y888]

create trigger trigger_test before insert on test
for each row
begin
	declare n int;
	select max(id) into n from test;
	if n is null  then
		set n=1;
	else
		set n=n+1;
	end if;
	case  
		when n<10 && n>=0 then 
			set new.order=concat('ord','0000',cast(n as char));
		when n<100 && n>=10 then
			set new.order=concat('ord','000',cast(n as char));
		when n<1000 && n>=100 then
			set new.order=concat('ord','00',cast(n as char));
		when n<10000 && n>=1000 then
			set new.order=concat('ord','0',cast(n as char));	
		else
			set new.order=concat('ord',cast(n as char));
	end case;
end //

[WWWWA]

DROP TRIGGER IF EXISTS trigger_test; DELIMITER $$ CREATE TRIGGER trigger_test BEFORE INSERT ON testa FOR EACH ROW BEGIN SET new.order =CONCAT('Ord',RIGHT(CONCAT('0000',LAST_INSERT_ID()+1),5)); END$$ DELIMITER ;

[lihuan2008a]

引用 6 楼 dong_y888 的回复:

create trigger trigger_test before insert on test
for each row
begin
	declare n int;
	select max(id) into n from test;
	if n is null  then
		set n=1;
	else
		set n=n+1;
	end if;
	case  
		when n<10 && n>=0 then 
			set new.order=concat('ord','0000',cast(n as char));
		when n<100 && n>=10 then
			set new.order=concat('ord','000',cast(n as char));
		when n<1000 && n>=100 then
			set new.order=concat('ord','00',cast(n as char));
		when n<10000 && n>=1000 then
			set new.order=concat('ord','0',cast(n as char));	
		else
			set new.order=concat('ord',cast(n as char));
	end case;
end //

引用 7 楼 WWWWA 的回复:

DROP TRIGGER IF EXISTS trigger_test; DELIMITER $$ CREATE TRIGGER trigger_test BEFORE INSERT ON testa FOR EACH ROW BEGIN SET new.order =CONCAT('Ord',RIGHT(CONCAT('0000',LAST_INSERT_ID()+1),5)); END$$ DELIMITER ;

这两个在一个人执行的时候没问题，但若有多个人操作时，发生并发时会不会不准确

[WWWWA]

有并发时，建议先锁表，进行完后再释放锁