mysql
drop table if exists tb;
create table tb(bh char(16),content varchar(20),date datetime,val int);
create trigger tri_newbh before insert on tb
for each row
begin
declare dt char(8)
declare bh_id char(16)
declare number int(1)
declare new_bh varchar(16)
set dt = date_format(curdate(),'%y%m%d') select max(bh) into bh_id from tb where bh like concat(dt,'%') if bh_id = '' or bh_id is null then set new_bh = concat(dt,'00000001') else set number = right(bh_id,8) + 1 set new_bh = right(concat('00000000',number),8) set new_bh=concat(dt,new_bh) end if set new.bh = new_bh end